【填空题】
1.什么叫电机转速差？什么叫转差率？*简答题*___
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答案
磁场放置速度n1与转速n之差n1-n称为转速差；转速差与磁场转速的比值叫做转差率，用符号s表示。
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A. Read J .K .Rowling's first book .
B. Go to buy a new Harry Potter book .
C. Watch BBC news about J .K .Rowling .
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Q2: Where did J. K. Rowling come up with the idea for Harry Potter?___
A. At a cafe .
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Q3: What are J. K. Rowling’s future plans?___
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D. She said she would work on more serious subjects .
【单选题】
Q4: What are the two speakers mainly talking about?___
A. J.K. Rowling's secret .
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【单选题】
Q1: What happened when Stephen tried to remove a bottle of milk from the refrigerator?___
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【单选题】
Q2: What did Stephen’s mother do when she came into the kitchen？___
A. She gave him a long lecture .
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【单选题】
Q3: What did Stephen’s mother teach him later?___
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【单选题】
Q4: What did Stephen learn from this experience?___
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【单选题】
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【单选题】
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【单选题】
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Q2: According to the passage, what is considered as bad luck?___
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【单选题】
Q3: Why is it considered bad luck to see a black cat crossing one’s path?___
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