According to the latest research, getting enough sleep is _____to maintaining good health and reducing stress.
#17753
A
practical
B
contradictory
C
essential
D
alternative
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Which is ____ country, America ____ Canada?
#19695
A
larger, or
B
a larger; and
C
larger, and
D
the larger, or
It is______ these stories can amuse her. 
#20297
A
sure
B
surely
C
certain
D
eager