单项选择题

Only recently ______ to realize the dangers caffeine (咖啡因) might bring to our health.

A. that scientists began

B. have scientists begun
C. scientists have begun

D. that did scientists begin
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单项选择题
My brother said he ______told his examination results by the time I next saw him．
A．would be
B．was to be
C．was to have been D．would have been
单项选择题
Kunming is unique in China ______ its temperature varies little, summer or winter.
A. in which
B. in that
C. for that
"D. but that
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