_____ he met with the difficulty did he realize the importance of group work.
| A．Even though | B．Not until | C．Only before | D．Ever since |
The _______ boy was last seen _______ near the East Lake.
| A．missing; playing | B．missing; play |
| C．missed; played | D．missed; to play |
Though I have often heard this song ______, I have never heard you ______ it.
| A．being sung; sang | B．sang; singing |
| C．sung; sing | D．to be sung; to sing |
The country itself didn’t have enough gas because of the war, so the government decided to ________ its gas supplies to other countries.
| A．hide away |
B．cut off |
C．insist on |
D．break up |
— Can you tell us what is important to a businessman?
— ________ information.
| A．Collect |
B．Collected |
C．Having collected |
D．Collecting |
— Can you tell us what is important to a businessman?
— ________ information.
| A．Collect |
B．Collected |
C．Having collected |
D．Collecting |