问题
单项选择题
插入铁心法的内容为：被试定子绕组插入尚未铸铝的转子铁心(或将被试转子插在定子铁心内)，在三相绕组上施加50Hz、1.3倍额定电压持续( )。
A．1min
B．2min
C．3min
D．5min
答案
参考答案：C
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插入铁心法的内容为：被试定子绕组插入尚未铸铝的转子铁心(或将被试转子插在定子铁心内)，在三相绕组上施加50Hz、1.3倍额定电压持续( )。
A．1min
B．2min
C．3min
D．5min
参考答案：C
| 用方框中所给词的适当形式填空，使短文正确、通顺，每个词限用一次。 | |
students usually study very hard for long 1 . This is very good but it doesn't 2 a lot, for an effective student must have enough sleep, enough food and enough rest and exercise. Every day you need to go out for a walk or visit some friends or some nice places. It's good for your study. When you return 3 your studies, your mind will be refreshed (清醒) and you'll learn more 4 study better. Psychologists (心理学家) 5 that learning takes place this way. Take English learning 6 an example. First you make a lot of progress and you feel happy. Then your language study seems 7 the same. So you will think you're learning 8 and you may give up. This can last for days or even weeks, yet you needn't give up. At some points your language study will again take another big 9 . You'll see that you really have been learning all along. If you get enough sleep, food, rest and exercise, studying English can be very effective and 10 . Don't give up along the way. Learn slowly and you're sure to get good results. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. |