Sep 14, 2010, 2:31 PM
Sorry for the delay in getting back to you, but I have been very busy.
It is not easy to answer the three questions, because the difference between this, that and it can be blurred at times. It depends on what the speaker has in mind.
I prefer this in the three questions because "this" can refer to the previous sentence, that is, the antecedent is the previous sentence. For example:
I arrived home late. This annoyed my father very much.
I arrived home late, which annoyed my father very much. (See http://www.polseguera.org/...clauses.php#return13)
I will not see my best friend Adam any longer, which does not have any influence...
...but you always corrected us, which definitely shows...
I still object to some questions in the exam. I prefer not to think about this.
I still object to some questions in the exam, which I prefer not to think about.