制动总泵的补偿孔()
A.防止液体从缸内漏出
B.将油缸内前后系统的压力分开
C.当活塞完全回位后,使得液体在储液罐和压力室间流动
D.密封以防灰尘和潮气
参考答案:C
根据旬意用括号内所给词的适当形式填空。
1.Thank you for ________ (organize)the class trip.
2.This is the ________ (child)playhouse.
3.His brother ________ (study)English very hard.
4.- Whose is this sweater? - It's ________ (he).
5.- What do you use to brush your ________ (tooth)? - toothbrush.
6.- Who ________ (cook)the meals in our home?
- My mother does.She is a very good cook.
7.- When is ________ (teacher)Day? - On September 10th.
8.We are really ________ (excite)at the exciting news.
9.He is ________ (dress)up as a ghost.
10.Do you have ________ (some)books about Halloween?
试述三相异步电动机工作原理。