Câu 4: By the time we arrive the other guests will have already started dinner.
=> The other guests will have already started dinner before we arrive.
Câu 8. He must pass his intermediate level English examination. That was obligatory
=> It is obligatory for him pass his intermediate level English examination.
Câu 9: The mother came and lived with them to take care of their children. That was their- request.
Cách 1=> It is requested that the mother (SHOULD) COME AND LIVE with their children to take care of them.
Sau cấu trúc It is requested (that) S + (SHOULD) + VERB (nguyên thể không chia với tất cả các ngôi).
Cách 2: The mother was requested to come and live with their children to take care of them.
Câu 11: .You lied to him, which was wrong.
=> It was wrong for/of you to lie to him.
=> It was wrong that you lied to him.
=> You were wrong to lie to him.
Câu 7. He is to blame for his mistakes. This is very necessary.
=> It is very necessary for him to be to blame for his mistakes.
** be to blame (for something) to be responsible for something bad: chịu trách nhiệm cho điều gì.