It was in the street ______ I live that I met Mr. Green.
| A.that | B.which | C.where | D.when | 
(2012·山东) After completing and signing it, please return the form to us in the envelope __________.
| A.providing | 
| B.provided | 
| C.having provided | 
| D.provide | 
"It’s sucha nice place," Mother said as she sat at the table __________ for customs.
| A.to be reserved | 
| B.having reserved | 
| C.reserving | 
| D.reserved | 
—Did you have any difficulty catching yesterday's lecture?
 —No. The professor spoke very clearly to make his speech easy __________.
| A.understood | 
| B.understand | 
| C.understanding | 
| D.to understand | 
You should understand the traffic role by now. You've had it __________ often enough.
| A.explaining | 
| B.to explain | 
| C.explain | 
| D.explained | 
I couldn't do my homework with all that noise __________.
| A.going on | 
| B.goes on | 
| C.went on | 
| D.to go on |