English Grammar Step by Step
UNIT 22 - Page 2
Insert the appropriate modal verb in the spaces provided.
When there is a verb in brackets, put it into the correct
‘I can play the drums,’ she said.
She said (that) she could play the drums.
‘We may sign the document tomorrow,’ they said.
They said (that) they might sign the document the following
‘She may/can/is allowed to finish work earlier today,’ he
He said (that) she might/could/was allowed to finish work
earlier that day.
If he had a car, he could visit them every day.
If you told her the whole truth, she might forgive you.
Could and might are the conditional or past forms of can and
may, respectively. See also units 24 and 26.
a He retorted that he (not) __________ take his younger brother
to the party with him. (He retorted that it was impossible
for him to take his younger brother to the party.)
b She said that he __________ be playing cards with his friends
or that he __________ be watering the plants, but that she
didn’t know for sure.
c He thought that his wife (not) __________ be seeing another
man, as he trusted her absolutely.
d He said that she __________ smoke there, as it was a
e They told her that he __________ bear the costs, but that he
needed time to think it over.
Can/Could you lend me twelve pounds, please? (a request)
We can/could go for a picnic tomorrow. (a suggestion)
You can take a biscuit if you like. (an offer)
You could come home for lunch! (an indirect invitation)
Both can and could are used for invitations, offers, requests
and suggestions. Could is more polite than can. Could may
also imply that the speaker is less confident about something.
a You __________ take the dog out for a walk.
b You __________ clear the table.
c You __________ come to the opera with us tonight.
d ‘We __________ free him from prison!’
e __________ you do the laundry, please?
16 Revision exercise.
a ‘He __________ be a sorcerer.’ (possibility)
‘You must be joking! There are no sorcerers nowadays.’
b ‘Where’s your mother?’
‘I don’t know. She __________ be nattering on about the
latest gossip. She loves it.’
c You (not) __________ mix business with pleasure. (It does
d You __________ clear away. You __________ also wash up. Your
mother doesn’t feel very well, and has just lain down a bit.
e The weathergirl said that it __________ rain in the south
of the country.
f She __________ quote many Shelley’s lines from memory. She
loves his poems.
g This __________ trigger off a revolution.
h He __________ be poor, but he’s happy.
i We __________ start off tomorrow. (This is not settled yet.)
j If you like, you __________ leave your message after the
k ‘__________ I have another steak, please?’
‘Of course you __________.’
l Ted __________ stir up trouble easily, so don’t go out with
m In my dream, there was a dragon with three heads. It
__________ breathe out fire and fly. Nobody __________ kill
it, but one day I __________ get rid of it for ever.
n __________ you possibly send me this report immediately,
o I was wondering if this __________ be true.
p He said that he __________ offer her a ride in his brand-new
car that afternoon.
q ‘Passengers (not) __________ smoke until the plane has taken
off,’ said the stewardess.
r If I won the lottery, I __________ buy a bungalow.
s Who __________ it be at this time? It’s nearly midnight.
t Paris __________ be fun at night.
u You __________ buy me a drink! I’ve run out of money.
v He __________ be wrong. What do you think of the whole
w ‘__________ he’s right?’
‘No, I don’t think so.’
x You (not) __________ break in on people like that. It’s
y My little daughter __________ dance beautifully.
z You __________ go to that concert twice. This time you’ll
have to stay at home and look after your brother.
17 Examples: (modal + have + past participle)
‘Why hasn’t he come yet?’
‘I don’t know, but he may/might/could have come across
somebody in the street.’
You could/might have taken the bus. (Why didn’t you take the
What can he have done this time?
Can they have done it?
May, might and could convey the idea that maybe something
(has) happened to somebody or something; or, in other words,
they are used when we are speculating about somebody or
something. Could and might show a less likely possibility.
Could and might can indicate that we did not do something
or something did not happen, although it was possible. They
are sometimes use to reproach somebody for not doing
something or not having done something: You could/might
have told me that the soup was piping hot!
Can is only possible in the interrogative. It often shows
surprise or incredulity. Could, and very occasionally might,
may sometimes occur instead of can: Could/Might they
have done it? Could and might suggest greater surprise or
incredulity, or that you think it is less probable.
a You shouldn’t have gone to the outer suburbs alone at night.
You __________ have been beaten to death. There’s a skinhead
gang in the area.
b You __________ have slunk out of the room. Why didn’t you do
c You __________ have called me to tell me when you were
d ‘Where are the kids? They should have been back by now!’
‘They __________ have gone gliding with their uncle.’
‘I don’t think so. I phoned him last night, and
he told me that he was coming here.’
‘Well, then, they __________ be with their grandparents.’
‘Or they __________ have gone for a swim in the sea. I’ve
told them a hundred times not to swim in the sea alone,
but they keep on doing it.’
‘They __________ have run away from home.’
‘You’re not serious, aren’t you?’
e ‘My brother went to climb the Alps last month, and hasn’t
come back yet.’
‘He __________ have been stuck in a blizzard.’
‘He __________ have had a fall and kill himself in the fall.’
‘Well, I don’t think so. He’s a very good climber.’
‘Anyhow, we’d better go to the police and report him missing.’
He can’t/couldn’t have stolen her purse yesterday. He’s been
abroad for a month already.
He may not/might not have stolen her purse yesterday. He’s
not the only thief in the area.
The first sentence implies that it is impossible that he
stole her purse yesterday, because he was abroad. The
second merely states that it is possible that he did not
steal her purse: perhaps it was another person.
a He (not) __________ have signalled left! I would have seen
b You (not) __________ have seen a dinosaur in the garden.
They were wiped out from the Earth’s surface millions
of years ago.
c ‘You (not) __________ have seen a UFO. UFOs don’t exist!’
‘I tell you I saw one!’
d ‘Mary hasn’t arrived yet!’
‘She (not) __________ have found her way back. She doesn’t
know the area very well, and it’s very easy to get lost here.’
‘Or maybe she decided to spend the night in town.’
‘She (not) __________ have done that! She’d have phoned us to
tell she was not coming.’
‘She (not) __________ have had enough petrol to get here.
There are no petrol stations on the road.’
‘You may be right. Let’s take the car and look for her.’
e He (not) __________ have found it out, or else he’d have made
a scene in the restaurant last night.
19 Examples: (obligation)
You must come home at nine o’clock.
I have to wear a chef’s hat in the restaurant I work for,
but I detest it.
Must expresses the speaker’s authority; have to,
external authority. The first sentence could have
been rephrase as follows: As I am your mother, I
want you to come home at nine o’clock; the second:
I do not want to wear a chef’s hat, but I have no
choice, because it is obligatory in the restaurant
I work for. If I say, however, I must wear a chef’s
hat in the restaurant I work for, it would imply
that I think it is necessary, although it has not
been imposed by me, but by the restaurant I work for.
a I hate getting up early, but I __________ (get up early to
work every day).
b The teacher: You __________read Romeo and Juliet for next
A student: What if we don’t!
The teacher: I consider it necessary for you to read it. If
you don’t, you’ll fail this term.
c You __________ help me with the domestic chores, sweetheart.
I can’t do them all.
d We __________ take the dog out to do his business three times
e This plant __________ be watered every evening, otherwise
He had to come home at nine o’clock last night.
I had to wear a chef’s hat in the restaurant I worked for
You will have to do the housework tomorrow.
You must do the housework tomorrow.
If you failed this examination, you would have to resit it
Must has only present and future meanings. Have to is used
instead of must for the simple past tense, the present perfect
tense, and so on, that is where must is not possible.
a As a child, I __________ do the washing-up every evening.
b They __________ spend the night there, as they had had a
c From now onwards, you __________ see to the household chores,
as I’ll be out working all day.
d He __________ take care of his little sister since their
parents passed away.
e If you quitted, they __________ employ another person in next
to no time.
21 Examples: (absence of obligation)
You needn’t/don’t need to/don’t have to come home at nine
I don’t have to/don’t need to wear a chef’s hat.
Semantically speaking, need not is the opposite of must; and
do not have to (or do not need to), of have to (or need to).
However, in practice, we very often use do not have/need to
instead of need not. Need not is only possible in the present
and future. In the past, present perfect, etc., not have to
(or less commonly, not need to) replaces need not.
a You (not) __________ eat all your lunch if you are not hungry.
b You (not) __________ take me to the station. My father can
c I (not) __________ feed my snake every day.
d You (not) __________ read the whole book. You must read only
the first and second chapters.
e We (not) __________ work. We come from a wealthy background.
22 Revision exercise.
a ‘Yesterday she was very rude to me!’
‘You __________ have visited her at the wrong time.’ (= It
is possible that you visited her at the wrong time.)
‘Well, actually, I think she was going to breastfeed her
b I __________ have made a terrible blunder, but this does not
allow you to treat me like dirt.
c ‘What __________ they be doing now?’
‘I don’t know, but they’re up to some mischief. Let’s go and
see what they’re doing.’
d You __________ have brought a file to cut the bars through!
(= It was stupid of you not to bring one.)
e ‘__________ I have a slice of cake?’
‘Of course you __________.’
f ‘Where’s the sergeant?’
‘I don’t know. He __________ have been wounded in action.’
‘Or he __________ have been killed in action.’
‘Or he __________ have got lost.’
‘He (not) __________ have got lost. He knows the area like
the back of his hand.’
g You __________ have explained it for the umpteenth time, but
I still don’t understand.
h I think you __________ report this incident to the
local authorities. (I find it necessary to do this.)
i A fart (not) __________ smell so bad! It must be a stink bomb.
j ‘This __________ be kept secret. Understand?’
k If she doesn’t come today, you __________ do the ironing.
(This is necessary.)
l You (not) __________ buy us a present. You’re going
through financial difficulties now.
m You __________ have reversed the charges! Why didn’t you!
n We __________ buy an answerphone as soon as possible. We
(not) __________ do without one.
o He said that they __________ buy an answering machine as
soon as possible, as they (not) __________ do without one.
p ‘Where are my car keys?’
‘You __________ have left them at home.’
‘Or I __________ have lost them.’
q I (not) __________ decide now: I __________ rethink our plan.
r I know it’s difficult to unwind after all you’ve been
through today, but you __________. It’ll make you feel good.
s ‘Excuse me, __________ you direct me to Trafalgar Square?’
t ‘Nobody __________ have seen me committing the murder: I was
u You (not) __________ tell me anything if you don’t want to.
v He (not) __________ go to bed early on Saturdays, as he
(not) __________ work on Sundays.
w We (not) __________ go to school yesterday. It was a
x ‘I dont want to see you any more!’
‘You (not) __________ be serious! I’m crazy about you. I
thought you loved me.’
y She (not) __________ be working for the CIA! She’s my
z The Sunday before last, they __________ break into the museum
and steal some valuable paintings.
They needn’t have bought any paint. He had some.
They didn’t need to/didn’t have to buy any paint. He had some.
The first sentence suggests that they did something
unnecessary, since they could have used his. In the
second example, we do not know whether or not the
action was carried out; probably it was not, as it
was not necessary.
a She (not await) __________ him for so long. She could have
gone home earlier.
b She (not go) __________ on foot. She could have gone in my
c He (not lie) __________ to his parents, so he didn’t.
d You (not come) __________ to meet me at the airport. I could
have caught a bus.
e They (not write) __________ to their parents, as they were
going to stay there for a short period of time, so they
Need/Must I finish my dinner, mum?
No, you needn’t/Yes, you must.
Need and must can be used interchangeably in the
interrogative. Need carries the idea that you do
not think it necessary; consequently, you expect
a negative response. Do I have/need to finish my
dinner, mum? is also possible, but it is less
formal and the short answer is different: Yes,
you do/No, you don’t.
a __________ I take out the rubbish now, mum? I’m watching
my favourite TV programme.
b __________ we mug up all the unit for the exam, Miss?
c __________ I give this wall another coat of paint?
d I know Tuesday is a public holiday, but __________ you take
Monday off as well? We have plenty of work at the office.
e __________ I wear this outfit? It’s ghastly!
There must be somebody in the house. The lights are on.
They must have told him everything. I saw them talking to him
last night, and this morning he knew everything. They are the
only people who could have done such a thing.
When there is enough evidence that something is true, we use
must. The opposite of must here is cannot: There can’t be
anybody in the house. It looks deserted. Americans, often use
have to in this sense: There has to be somebody in the house.
a ‘Victor is as poor as a church mouse, and I saw him with a
wad of bank notes last night.’
‘So he __________ be the person who robbed the local bingo
hall last night, because it’s impossible for him to have
such a lot of money.’
b You __________ have been eavesdropping outside the door,
as we haven’t told this to anybody.
c Majorca __________ be overrrun with tourists at this time of
the year. So we’d better go somewhere else, since I don’t
like crowded places.
d ‘Daniel’s parents say that his son has got a girl-friend, and
that she’s an angel. They met her the other day.’
‘They __________ have taken to her. He has had to break up
all the engagements he has had until now owing to his parents.
They were always telling him that he deserved a better girl.
e ‘Martin treated me like dirt last night. He had always
been friendly towards me.’
‘He __________ hold a grudge against you for not letting him
join the party.’
You must not smoke here. It is a non-smoking compartment.
You can’t park here. It’s forbidden.
Students may not talk during the exams.
You shouldn’t/oughtn’t to drink so much.
Must not, cannot and may not express prohibition.
Must not indicates that authority originates from
the speaker or that the speaker shares this opinion.
It, too, implies that if we do something the
consequences will not be very good: You mustn’t
drink bleach. Cannot has a similar meaning to
must not, but it conveys a more external authority.
May not is mainly used in formal notices or
instructions. Should not (or ought not to)
suggests that the proper thing is not being done.
a You (not) __________ smoke in bed!
b Visitors (not) __________ take photographs of the paintings.
c You (not) __________ poke around in your sister’s room. She
needs her own privacy.
d You (not) __________ carry a loaded pistol. It’s very
e You (not) __________ drive so fast here. There’s a speed
A modal verb + have + a past participle always refers to the
past. See unit 23, section 16.
Could often carries the idea that you are even more hisitant
about the chances of something happening than might.
See section 29 in this unit.
Be to can also express obligation. See unit 6, part 1,
See unit 6, part 4, section 4.
At times, the authority does not come from the speaker, but
he or she agrees with it. In this case, we use must.
The obligation does not originate from the speaker, but from
The speaker imposes the obligation or considers it necessary.
In reported speech, must is often left unchanged:
His mother said that he must come/had to come/was to
come home at night o’clock/His mother ordered him to
come home at nine o’clock.
For reported speech, see unit 26.
In the affirmative, need is followed by to: I need to tell
her what occurred.
See section 23.
See unit 2, section 12.
See section 18 in this unit.
See section 8 in this unit.
Had better not has a similar meaning: You’d better not tell
them a word, or else they’ll tell everybody. See unit 6, part
4, section 10.
Be to is an alternative to may not: Students are not to talk
during the exams. See unit 6, part 1, section 7.
Author: Miquel Molina i Diez
Pages: 1, 2, 3 and the key
1 Negative and interrogative sentences (Page 2 and the key)
2 Short answers (Page 2 and the key)
3 Question tags (Page 2 and the key)
4 Questions and exclamations (Page 2 and the key)
5 So, neither, nor, either (the key)
6 Be, used to, would, be/get/become used to, dare, have, get, become, grow, go, turn, fall and feel (Page 2 and the key)
7 Verb tenses: forms (Page 2 and the key)
8 Irregular verbs
9 Verb tenses: uses (Page 2, Page 3, Page 4, Page 5 and the key)
10 Personal pronouns, possessives and reflexive pronouns (Page 2 and the key)
11 The genitive case (the key)
12 Singular and plural nouns (Page 2 and the key)
13 Gender (the key)
14 A, an, some, any, no, not, none, each, every and the; compounds of some, any, no and every (Page 2, Page 3 and the key)
15 Neither, not...either, none, not...any, both and all (the key)
16 A few, few, a lot, lots, a little, little, many, much, no and plenty (the key)
17 Enough, too, so and such (the key)
18 Comparative and superlative sentences (Page 2 and the key)
19 Adjective order (the key)
20 Relative clauses (Page 2 and the key)
21 Do and make (the key)
22 Modal verbs (Page 2, Page 3 and the key)
23 Infinitives, gerunds and present participles (Page 2 and the key)
24 Conditional sentences (Page 2 and the key)
25 Passive sentences (the key)
26 Reported speech (Page 2 and the key)
27 Purpose (the key)
28 Word order (the key)
29 Inversion (the key)
30 Connectors (Page 2 and the key)
31 Prepositions (Page 2, Page 3 and the key)
32 Phrasal verbs (the key)