The helicopter is able to hover in ___________ powered rotors ...

★ TOEFL

The helicopter is able to hover in ___________ powered rotors produce lift even at zero forward speed.

A. flight because of the

B. flying the

C. the flying of the

D. flight because the

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North Carolina’s outer banks are a chain of low, narrow islands ___________ the mainland from the frequent Atlantic storms in the area.

A. they buffer

B. that buffer

C. to buffer them

D. that they buffer