【单选题】毛泽东明确提出要走一条有别于苏联的中国工业化道路是在( )中。
【单选题】They ___ every means, but the engine __ work.
【单选题】Every means , but none proved .
B.
have been tried; successful
C.
has tried; to be successful
D.
has been tried; successful
【单选题】Every possible means ____, but none ____ successful.
C.
has been tried; proves
D.
is being tried; is proved
【单选题】_____many times, they succeeded _________ the experiment.
A.
Having tried; in doing