___ is the most useful invention?
| A．Do you think which of these | B．Which of these you know |
| C．Which of these do you know | D．You know which of these |
There is not one of us wishes to help you . We are doing our best .
| A．who | B．that | C．as | D．but |
—Alice, you feed the bird today； ？ —But I fed it yesterday.
| A．do you | B．will you | C．didn’t you | D．don’t you |
Our school is no longer ______ is was 10 years ago, _______ it was not well equipped.
| A．what; which | B．that; which | C．what; when | D．that; where |
—I’d like to invite you to my birthday party this evening.
—Thanks, but ____ I’ll have time I’m not sure at the moment.
| A．while | B．whether | C．if | D．when |
I am afraid I am not fit for the job, because it is one requires a lot of patience.
| A．who | B．that | C．what | D．where |