【单选题】压力控制阀中,出口压力保持恒定的阀是( )
【单选题】压力控制阀中,使出口压力低于进口压力,并使出口压力保持恒定的阀是 。
【单选题】在压力控制阀中,出口压力保持恒定的阀是:
【单选题】Climbing is one of _____, I think. [ ]
A.
the most difficult sport
B.
the most difficult sports
【单选题】In which type of organization is team building likely to be most difficult?
【单选题】Lesson Three is Athe most difficult lesson, Bbut it isnt Cthe most difficult lesson Din Book Four.
【单选题】Climbing is one of ______, I think. [ ]
A.
the most difficult activity
B.
the most difficult activities
C.
most difficult activity
D.
most difficult activities