如图为刚性夹持抛块限速器示意图，图中代号1表示的是（）。
A、绳钳压簧
B、绳钳
C、绳轮
D、打板碰块
参考答案：D
Almost ____ of the students in this class ____ glasses, that is, ____ of them.
A．two thirds; wear; 60 percent
B．two thirds; wear; 60 percents
C．two third; wears; 60 percent
D．two third; wears; 60 percents
CHTA型锅炉给水泵是如何保证泵心和简体之间的密封的？
