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【单选题】
131 轴端密封如下 : 1毡圈密封2唇形密封圈密封3机械密封4缝隙沟槽密封5 (迷宫)密封。其中( )属于接触式密封。 答案是( ) ( A )12 ( B )123 ( C )25 ( D )1245A.
a
B.
b
C.
c
D.
d
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举一反三
【单选题】It’s no good ______ when you don’t really.
A.
to pretend to understand
B.
pretend to understand
C.
pretending understanding
D.
pretending to understand
【简答题】Conjuega en futuro imperfecto saber yo tú él,ella,usted nosotros,tras vosotros,tras ellos,ellas,ustedes
【单选题】It’s no good ___ money on make-up.
A.
of you to waste
B.
for you to waste
C.
to waste
D.
your wasting
【单选题】It’s no good ____ until I’m reasonably sure when I’ll be able to go for my holiday.
A.
to decide
B.
to have decided
C.
deciding
D.
being decided
【单选题】It’s no good ____ a lot without doing anything.
A.
to talk about
B.
talking about
C.
to talk
D.
talking
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