The main cause of valve failure is contamination of hydraulic fluid.

A. The bolt will be at the 2 o’clock position when you look at the pump from the rear.

B. The rivet is installed on the 2 o＇clock position of the pump when looking from rear to front.

C. Look at the bolt installed on the pump from rear to front at the 2 o＇clock position.

A. 改版是指对现有数据进行更新。

B. 手册修订是指对其内容进行升级更新。

C. 修订是指对现有手册中信息的修改。

A. Oxygen occurs occasionally.

B. Oxidation occurs very easily.

C. Oxygen happens very easily.

A. 当有几个英语单词表达的是同一事物时（同义词）， STE 允许从这些同义词中选择一个使用除非另有规定。

B. 当同一词在英语中有多个词义（多义词)时，STE允许使用其中一个意义而不允许使用其他意义。

C. 当英语中有几个词表示同一事物(同义词)时，STE允许使用这些同义词中的一个，而不允许使用其他的。

A. These must be shown on the wiring diagram under some specific conditions and wires are colour coded.

B. Wires are coded in color in certain condition and these should be marked on the wiring diagram.

C. In some cases, wires are color coded and these should be indicated on the wiring diagram.

A. Check such system to determine the cause of interference.

B. Examine part of the system to find the cause of the interference.

C. Examine all of the system to find the cause of the interference.

A. Not only the basic principle of the reciprocating engine is simple, and also the assembly.

B. The basic principle of a jet engine is simple, and so is its construction.

C. The basic principle of the propeller driven engine is simple, as well as the installation.

A. Do not install 0.1 mm thick shims.

B. Do not install shims which are more than 0.1 deep.

C. Do not install shims that are more than 0.1 mm thick.

A. The numbering of paragraphs and subparagraphs within a section is not required.

B. No numbers of paragraphs and subparagraphs is required in a section.

C. The numeral order of the paragraphs and subparagraphs is unnecessary in a section.

A. 该限制应在飞机处于起落架上或提升装置上时使用。

B. 如果飞机在起落架上或被顶起，请查阅此文件。

C. 该限制适用于飞机在起落架上或千斤顶上。