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【判断题】
超声探头发射超声波时,电能转换成声能,接收超声波时,声能转换成电能,因此探头又称换能器。A.
正确
B.
错误
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【单选题】—_________ has Bob been collecting stamps? —Since he was 8 years old. [ ]
A.
How often
B.
How long
C.
When
【单选题】— has Bob been collecting stamps? — Since he was 8 years old. [ ]
A.
How often
B.
How long
C.
When
D.
How much
【简答题】普通螺纹的公称直径是指内螺纹的 ,外螺纹的 ,内螺纹的公称直径用 代号表示,外螺纹的公称直径用 代号表示。
【单选题】How long will it take Bob to get to the party?
A.
About 5 minutes.
B.
About 10 minutes.
C.
About 15 minutes.
D.
About 20 minutes.
【简答题】鲍勃将跳远的世界纪录保持了多久？ How long did Bob __________ the world __________ in the long jump?
【简答题】与外螺纹( )或内螺纹( )相重合的假想圆柱面的直径称为大径。外螺纹大径用( )表示,内螺纹大径用( )表示。
【单选题】Bob: How long have you lived here? Sue: _________.
A.
Since the beginning of the year.
B.
In 1990
C.
Not long ago
D.
Only until the end of the year
【单选题】----What did Bob ask you just now? ----He wanted to know how long __________when I reached the cinema.
A.
had the film been on
B.
the film had started
C.
the film had been on
D.
had the film ended
【简答题】内螺纹公称直径用( )表示 ; 外螺纹 公称直径用( )表示。
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