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【多选题】
能调节系统压力的大小，且能维持系统压力近于恒定的压力阀称为溢流阀。其功用是（）。A.
在变量泵供油系统中作安全阀使用
B.
在节流调速系统中作溢流阀使用
C.
在定量泵系统中，还可作卸荷阀使用
D.
在某些情况下可作换向阀使用
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举一反三
【单选题】听力原文： Officials of the World Food Program, WFP, said they are receiving information that famine has gripped parts of Central Afghanistan. WFP officials say as the winter snow begins to melt and high m...
A.
melting snow begins to block the mountain paths.
B.
the Taliban have destroyed existing food stocks.
C.
the Taliban are hindering food deliveries.
D.
an emergency air-lift of food was cancelled.
【单选题】The Voice of China is such a popular program with viewers has produced many a music-lover.
A.
who
B.
that
C.
where
D.
as
【单选题】What does the writer think of the TV program?
A.
Dull.
B.
Crazy.
C.
Interesting.
D.
Serious.
【单选题】How would you describe the writer's attitude towards the Canadian immersion program?
A.
Supportive.
B.
Unenthusiastic.
C.
Balanced--prepared to weigh up the pros and cons.
D.
Critical.
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