The research is so designed that, once _______, nothing can be done to change it.
#80383
A
begins
B
having begun
C
begun
D
Beginning
推荐题目
——Did you know any Chinese before you arrived in Beijing?——Never ________it, actually.
#80572
A
had I learned
B
have I learned
C
I have learned
D
I had learned
—— He promised to come to see you. —— But he ＿＿＿＿＿. I’ve been all alone.
#84535
A
didn’t
B
wouldn’t
C
hasn’t
D
won’t
Only at that time how much time she had wasted.
#81919
A
Mary did know
B
did Mary know
C
does Mary know
D
Mary does know
Never before______ so highly successful in his attempts to forecast the weather accurately on a small scale．
#84505
A
man has been
B
man is
C
has man been
D
will be man