On the ground, the APU allows the airplane___（不依赖于） ground support equipment by supplying air for main engine start or air conditioning and electrical power.
A.rely on
B.depend on
C.tie to
D.to be independent of
正确答案是D
On the ground, the APU allows the airplane___（不依赖于） ground support equipment by supplying air for main engine start or air conditioning and electrical power.
A.rely on
B.depend on
C.tie to
D.to be independent of
正确答案是D