Some plants can take in carbon dioxide we breathe out and give ______ oxygen to us.
| A．in case | B．in turn | C．in return | D．in addition |
It’s quite some time ______ our teammate Wang Qiang got injured in the foot, but we firmly believe it won’t be long _________ he recovers from it.
| A．since; before | B．before; since |
| C．after; when | D．when; after |
----Jack can’t concentrate on his lessons recently.
----Yes, that might _____ his low score in the last test.
| A．stand for | B．apply for | C．account for | D．call for |
There were two boys in the lab, _______ did the experiment successfully.
| A．the clever of whom | B．the cleverer of whom |
| C．the cleverer of them | D．the more clever of them |
Every boy and every girl as well as some teachers who_____ to visit the museum______ asked to be at the school gate before 6 :00 in the morning.
| A．are ; are | B．is; is | C．is ;are | D．are ;is |
__________both sides accept the agreement will a lasting peace be established in this region.
| A．If only | B．Only if | C．unless | D．As long as |