Scientists say it may be five or ten years___________ it is possible to test this medicine on human patients.
| A．since | B．before | C．after | D．when |
He ______ on the bed_____ to his parents that blackbirds had_____ their eggs on Mars.
A. lay; lying; liedB. lied; lied; lied
C. laid; laid; laid D lying; lied; laid
Children’s curiosity may _____________ many useful inventions.
| A．lead to | B．take place | C．gather in | D．bring away |
—I want to know if I__________ smoke here.
—No, you _________.Could you see the sign “NO SMOKING” there?
| A．can; needn’t | B．must; can’t | C．shall; won’t | D．may; mustn’t |
Everyone has periods in their lives ______ everything seems very hard.
| A．when | B．where | C．which | D．that |
I can’t thank you ______ much because without your help I ______ have won the first prize.
| A．too; wouldn’t | B．very; shouldn’t | C．that; might not | D．so; couldn’t |