UBFA模块为BBU风扇盒模块，STATE指示灯快闪（0.25s亮，0.25s灭）说

实践具有以下三个特点：              、                 、_____     ___。

As a young man, Comrade Zhou Enlai ________ the students' movements and later ________ the Communist Party of China.

A．joined; took part of

B．took part in; joined

C．joined in; took part in

D．took part of; joined

组成一台计算机所有固定装置的总称为硬件。

高压缸临界转速是（）rpm。

A.2612

B.3500-4000

C.7475

D.5000

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