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
---Mum, I hurt my leg when I climbed the tree.
--- You ___ that tall tree. I’ve told you many times.
A. mustn’t have climbed B. shouldn’t have climbed
C. couldn’t climb D. may not climb
