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【简答题】
气门导管的作用是为气门的往复直线运动起()作用,使气门与气门座(),此外,气门导管在气门杆和气缸盖之间起()作用。
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举一反三
【单选题】When moist air moves over a cooler surface, then may occur.
A.
frontal fog
B.
steam fog
C.
advection fog
D.
radiation fog
【单选题】【单选】When moist moves over a cooler surface, then _____ may occur.
A.
advection fog
B.
radiation fog
C.
frontal fog
D.
steam fog
【单选题】Most of us have come to realize that it is about time (that) we ______ effective measures to prevent all kinds of pollution.
A.
take
B.
took
C.
must take
D.
shall take
【单选题】People begin to know that most environmental problems exist because necessary measures for preventing them _____ taken in the past. [ ]
A.
are not
B.
were not
C.
hadn't been
D.
wouldn't be
【单选题】When moisture air moves over a cooler surface, then may occur.
A.
advection fog
B.
radiation fog
C.
frontal fog
D.
steam fog
【单选题】Most(75)measures involve data encryption and password.
A.
security
B.
hardware
C.
display
D.
program
【单选题】Most environmental problems exist because adequate measures for preventing them ______ taken in the past.
A.
was not
B.
were not being
C.
were not
D.
was no to be
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