56. It has a single shaft and operates at a constant speed.

5、Always use these words with their approved meanings.

4、有些工作或流程由几个基本操作组成,每个操作下面有若干小步骤或工作项。

3、Access doors and panels in a zone are identified by the zone number and a two or three letter suffix. 区域内的门禁门和面板由区域号和两个或三个字母的后缀来标识

2、The airplanes were delivered with recommended inspection programs to keep them airworthy.

1、The properties of these sealants prevent corrosion.