_______the thick clouds, you would find the kite in the sky easily.
| A．Had it not been for |
| B．If it were not |
| C．If it had not been for |
| D．Were it not for |
Scientists say it may be five or six years _____ it is possible to test this medicine on human patients.
| A．since | B．after | C．before | D．when |
It was not he took off his dark glasses I realized he was a famous singer.
| A．when; that | B．until; that | C．until; when | D．when; then |
The number of children who___________ both parents to Aids ________ also expected to rise, reaching more than 26 million in 2010.
| A．has lost; is | B．have lost; are | C．has lost; are | D．have lost; is |
__________at the gate of the theater, Susan found the ticket for the play was left at home.
| A．To arrive | B．On arriving | C．As arriving | D．While arrived |
The house_________was destroyed has now been repaired.
| A．the roof of it | B．whose roof | C．its roof | D．the roof of that |