问题

Stand up _____ you fall down, and I’m sure you’ll succeed in time.[ ]
A: until
B: where
C: before
D: which
B: where
C: before
D: which
正确答案是:
同类题型
, what we have done is destroying the earth; only by changing we live we save it.
His father feels like ________a walk after dinner while his mother would like ______TV at home.
_____________ that I couldn’t be absorbed in the work.
Nick has problems _______ .He has a sore leg.
It is _____taking the trouble _____ a job fully to new employees.[ ]