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【判断题】
W18Cr4V,W6Mo5Cr4V2属于高速钢。该类钢经高温淬火及多次高温回火后具有高的强度、硬度和耐磨性,红硬性温度达到600°C,故该类钢主要用于制造切削速度较高的刀具(如车刀、铣刀等)和形状复杂、负荷较重的成型刀具(如齿轮铣刀、拉刀等)。( )A.
正确
B.
错误
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皮皮学刷刷变学霸
举一反三
【单选题】We had to wait a long time to get our passports, __________?
A.
won't we
B.
don't we
C.
didn't we
D.
shouldn't you
【判断题】()“Promises” like Why don't we get together one of these days? , though frequently made by Americans, are no commitment.()
A.
正确
B.
错误
【单选题】Things will turn bad if we ______ there on time.
A.
not get
B.
don't get
C.
won't get
【单选题】The reason that scientists cannot cure a common cold is_____.
A.
we don't know how we get cold
B.
we aren't sure the exact kind of cold viruses
C.
we don't know when we will catch cold
D.
we aren't sure the exact scientific method
【简答题】有一根折射率为1.6的玻璃棒,其一端为曲率半径r=30mm的凸球面,另一端为磨砂的平面,问该玻璃棒多长时,远处的物体能清晰成像在磨砂平面上。
【简答题】A．We don't know the long-term effects of it. B．We don't have the technology to get rid of it. C．It is a cause rather than a symptom. D．We have to accept the reality and try to change society.
【单选题】有一根折射率为1.6的玻璃棒，其一端为曲率半径r=30mm的凸球面，另一端为磨砂的平面，问该玻璃棒长为( )mm时，正好使远处的物体能清晰地成像在磨砂平面上。
A.
50
B.
80
C.
100
D.
120
【单选题】They don't think we can get first place in the speech contest, ________ ?
A.
do they
B.
don't they
C.
can we
D.
can't we
【单选题】If we don't hurry up, everything ________ by the time we get to the party.
A.
will be eaten
B.
is eaten
C.
has been eaten
D.
will have been eaten
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