单项选择题

We must______ that the experiment is controlled as rigidly as possible.

A．secure
B．ensure
C．assure
D．issue
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单项选择题
After having gone ______far, George did not want to turn back.
A．enough
B．much
C．such
D．that
单项选择题
It was as a physician that he represented himself, and_________he was warmly received.
A．as such
B．such as
C．as that
D．so that
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