振动电机所用轴承，需采用（）润滑。
A.手动干油式
B.稀油滴注
C.涂抹式
D.油浸式
参考答案：A
I have been convinced that the print media are usually more ________ and more reliable than television.[ ]
A. accurate
B. ridiculous
C. urgent
D. shallow
如何鉴别器质性与功能性杂音？
