You can’t go back home______you finish your homework.
| A．if | B．until | C．so | D．because |
The librarian told us that we could borrow at most three books __________.
| A．at a time | B．all the time |
| C．from time to time | D．on time |
— Why do English people talk so often about the weather when they start a conversation?
— Because the weather is a __________ subject.
| A．serious | B．good | C．close | D．safe |
Checking your answers before handing in your paper can help you __________ mistakes.
| A．make | B．provide | C．avoid | D．advise |
It’s kind __________ Yao Beina to donate her corneas (眼角膜) _________ three people in need.
| A．of; to | B．for; to | C．of; for | D．for; for |
Many people do not realize the importance of health __________ they have fallen ill.
| A．since | B．until | C．while | D．After |