In the last paragraph the author ______.
A. compares the behaviors of sleepers and hiders
B. offers an explanation for the survival of sleepers and hiders
C. analyzes how a changing environment affects SLOH-ers
D. emphasizes what can be learned from SLOH-ers
【C2】
A. route
B. track
C. path
D. trace
What's the minimum weight a shipment must reach in order to be transported by air？
A. No restrictions.
B. 68kg.
C. 122kg.
D. 997kg.
The phrase "a leg up" in Paragraph 2 probably means ______.
A. an instinct
B. an advantage
C. a fight
D. a chance
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