Question 25: "The last time we visited our grandparents was two years ago." This means we haven't visited them since then.

A. We haven't visited our grandparents for two years. This is the correct paraphrase.
B. Our visit to our grandparents lasted two years. (Incorrect - This means the visit itself took two years.)
C. Two years ago, we often visited our grandparents. (Incorrect - This implies repeated visits in the past.)
D. At last we visited our grandparents after two years. (Incorrect - This implies a long-awaited visit.)
Correct answer: A

Question 26: "It's a pity that Sam won't participate in the national heritage preservation campaign." This expresses a wish that Sam would participate.

A. I wish Sam will participate in the national heritage preservation campaign. (Incorrect - "will" is not used in "I wish" clauses for present/future wishes.)
B. I wish Sam would participate in the national heritage preservation campaign. This is the correct form for expressing a wish about someone else's actions in the present/future.
C. I wish Sam wouldn't participate in the national heritage preservation campaign. (Incorrect - This expresses a wish that Sam wouldn't participate, the opposite of the original meaning.)
D. I wish Sam won't participate in the national heritage preservation campaign. (Incorrect - "won't" is not used in "I wish" clauses.)
Correct answer: B

Question 27: "If/I/have/enough/money/me/now/I/buy/that/coat." This is a conditional sentence type 2 (unreal present). The structure is: If + past simple, would + base verb.

A. If I has had enough money with me now, I would buy that coat. (Incorrect - "has had" is not the past simple.)
B. If I had enough money with me now, I will buy that coat. (Incorrect - "will" is not used in the main clause of a type 2 conditional.)
C. If I had enough money with me now, I would have bought that coat. (Incorrect - This is a type 3 conditional (unreal past).)
D. If I had enough money with me now, I would buy that coat. This is the correct type 2 conditional.
Correct answer: D

Question 28: "The doctor/ask/him/cut/down/sweet food/drinks." The verb "ask" requires an infinitive ("to + verb") when asking someone to do something.

A. The doctor asked him cut down on sweet food and drinks. (Incorrect - Missing "to" before "cut.")
B. The doctor asked him to cut down on sweet food and drinks. This is the correct form.
C. The doctor asked him to cut down sweet food and drinks. (Incorrect - "on" is needed after "cut down")
D. The doctor asked him cut down sweet food and drinks. (Incorrect - Missing "to" and "on")
Correct answer: B