---- John ,why are you so upset?
----I _________ my cellphone all morning but it is nowhere to be found.
| A．am looking for | B．have looked for |
| C．have been looking for | D．had looked for |
----Whose advice do you think I should take?
----________.
| A．It doesn’t matter | B．That’s it | C．It’s up to you | D．Either is OK |
Leaves are found _______ all kinds of trees, but they differ greatly ________ size and shape.
| A．in; on | B．in; from | C．on; by | D．on; in |
To save class time, our teacher has ________ students do half of the exercises in class and complete the other half for our homework.
| A．we | B．us | C．our | D．ours |
Darwin counted 225 flowering plants, ________ he collected and brought home 193.
| A．that | B．in that | C．of which | D．all of which |
The government has taken some measures to reconstruct the earthquake-hit areas, but it must be some time ________ everything returns to normal.
| A．since | B．after | C．unless | D．before |