电动机轴承过热是轴承室内缺油,应加润滑脂充满( )油室,或加润滑油至标准油面。
A.1/3
B.2/3
C.1/2
D.1/4
参考答案:B
Look,read and match. (连句子组成对话)
(1) Good afternoon, Mr. Black. A. Nice to meet you, too.
(2) Nice to meet you. B. Welcome.
(3) We have a new friend today. C. Good afternoon, Mr White.
美国国防部安全标准定义了 4 个安全级别,其中最高安全级提供了最全面的安全支持, 它是______。
A.A 级
B.B 级
C.C 级
D.D 级