单项选择题

First published in 1927, the charts remain an______ source for researchers.

A) identical
B) indispensable
C) intelligent
D) inevitable
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单项选择题
You should try to ______ your ambition and be more realistic.
A) reserve
B) restrain
C) retain
D) replace
单项选择题
As he has______ our patience, we'll not wait for him any longer.
A) tom
B) wasted
C) exhausted
D) consumed
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