1. B. had finished is the correct answer. The sentence implies that the meeting started after the preparations were completed.

2. D. haven't got is the correct answer. The speaker is expressing that they haven't had the opportunity to travel due to their busy schedule.

3. C. had driven-remembered is the correct answer. The sentence indicates that the action of driving happened before the action of remembering.

4. A. is having is the correct answer. The sentence suggests that the student is currently experiencing a headache.

5. C. never forgets is the correct answer. The sentence implies that the mother consistently forgets her keys.

6. A. don't need is the correct answer. The sentence indicates that the speaker currently doesn't require more help.

Exercise 2: Rewrite the sentences.

1. He worked at that company until 2015.

2. It is a long time since the artists showed their design.

3. This is the last time the artists showed their design.

4. Did you begin having many friends when you entered high school?

5. You began having many friends when you entered high school.

6. The girl last took part in a competition in the last summer.

7. It is the last time the girl took part in a competition.

8. The girl has taken part in a competition in the last summer.