Read these sentences and fill in the gaps with the correct verb form in the past perfect. Example 0. John
his rabbits by 9 o'clock yesterday. (feed)
Answer 0. had fed.
1. Before Ken ran to Kerry's house, he
I
him. (phone)
2. Laura repaired her glasses because her brother
them. (break)
3. There were no sausages left when I came back. The dog
them. (eat)
ответить! !

1 must -Она очень плохо говорит по-английски, она должна усердно учиться 
2 can -Можешь одолжить мне свой словарь?
3 could -Он не мог говорить по-английски в году
4 has -Он должен остаться здесь на месяц
5 had, could- Никто не встретил меня, когда я приехал, потому что я должен был приехать на 10-часовом поезде, но я не смог достать на него билет.
6 could -Паули не смогла пойти на встречу на неделе. Она болела.
7 I will be able- Я смогу поговорить с ним завтра, а сейчас у меня нет времени
8 had -Обычно я не работаю по субботам, но в субботу мне пришлось работать 

Scientific activity is the main engine of progress and it opens up endless prospects for the future of society and civilization.

Общий:

Is scientific activity the main engine of progress?

Does scientific activity open up endless prospects for the future of society and civilization?

Альтернативный:

Is scientific activity the main engine or the main stop of progress?  

Does scientific activity open up or close endless prospects for the future of society and civilization?

Разделительный:

Scientific activity is the main engine of progress, isn't it?

Scientific activity opens up endless prospects for the future of society and civilization, doesn't it?

Специальный:

What is scientific activity?

What does scientific activity open up?

К подлежащему:

What is the main engine of progress?

What opens up endless prospects for the future of society and civilization?