单项选择题

Only after ______ made hundreds of experiments ______ succeed in solving the problem.

A．they had; did they
B．had they; they did
C．they had; they did
D．had they; did they
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单项选择题
Will you lend me the book Yes, I ______ .
A．will
B．shall
C．can
D．may
单项选择题
--Mary has got the first ______ in the competition. --Let's ______ a celebration, then.
A．praise; have
B．place; to
C．prize; hold
D．price; make
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