正确答案: A

the running-in period

题目：All the rings are slightly rounded on their external top and bottom edges to keep the oil film on the cylinder liner during （） for new piston rings.

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学习资料的答案和解析：

[单选题]可靠性定义中所述及的“规定的条件”，包括（）。Ⅰ.环境温度、压力、湿度；Ⅱ.振动；Ⅲ.承受的负荷

Ⅰ+Ⅱ+Ⅲ

[单选题]（） usually helps to induce air movement to assist combustion.

The piston movement

[单选题]A level gauge for a tank is to （）.

give the contents

[单选题]The governor of a generator engine is to （）.

make the engine run at nearly constant speed

[单选题]Valve overlap is the period during which （）.

both valves are ope

[单选题]In using reduction gears to obtain efficient propeller speeds, （）.

they are connected to the engine with a flexible coupling