噪音防止的措施有吸音主要用某种材料吸收，还有____用于单体机组，以及___ 、____。

叶片式水泵是靠装有叶片的____高速旋转而提升液体的。

All people, whether they be rich or poor, strong or weak, privileged or deprived，are interdependent, and _______ the common task of seeking to achieve mankinds full potential

Many boys enjoy _______ football, basketball or baseball

－ What does the sign over there read － “No person ________ smoke or carry a lighted cigarette, cigar or pipe in this area”

给水泵（P309）的额定转速是_________r/min。

29．__________ when you are on the bus or bike．

本题那项不符合水泵结合器的设置要求：_____

在______中，①用于防止信息抵赖；②用于防止信息被窃取；③用于防止信息被篡改；④用于防止信息被假冒。

Duty is an act or a course of action that people __________you to take by social customs, law or religion.

消防水泵的吸水方式宜采用______

目前汽车发动机上采用的冷却水泵主要是________。