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【单选题】
离心泵的液体噪音通常是由于泵的吸入性能恶化发生汽蚀现象引起的,可能原因是________。A.
叶轮局部腐蚀、磨损或淤塞使动平衡破坏
B.
吸入管因生长海生物太多变细
C.
泵轴弯曲、电机或泵轴承损坏、叶轮与密封环擦碰
D.
联轴节对中不良
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举一反三
【单选题】An attempt on the part of the author of this passage to give a more informal tone to his writing occurs in ______.
A.
paragraph 2
B.
paragraph 4
C.
paragraph 5
D.
paragraph 7
【单选题】W h ich sentence below shows a confident tone?
A.
The audit was performed by a certified accountant.
B.
All agenda items for the meeting were selected by the human resources department.
C.
The report was written by George and was approved by the district manager.
D.
The president will give the top sales representative an award at the dinner this evening.
【简答题】The tone of the speech is ( ) and ( ) .
【单选题】8)The tone of this essay is_________.
A.
calm and objective(客观的)
B.
serious and thought-provoking(发人深省的)
C.
humorous and satirical(讽刺的)
D.
sentimental(感伤的) yet philosophical (富有哲理性的)
【单选题】听力原文：W: What do I do after I put the money in ? M: Listen for the dial tone, Jane, and then dial the number you want. Q: What is Jane learning to use? (4)
A.
A television set.
B.
A washing machine.
C.
A public telephone.
D.
A candy machine.
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