数控机床是用代码化的()量来控制机床的。
参考答案:数字
— Betty ______ john and is our headmaster now.
— Really? In my opinion, she herself should be ______ by someone else, too.[ ]
A. has taken place of; replaced
B. has placed; taken place
C. has taken the place of; replaced
D. taken place of; replace
润滑油外部泄露的原因有:()(1)油管及接头泄露(2)垫片或油封处泄露(3)油底壳内液位过高(4)呼吸器堵塞。
A.(1)(2)(3)
B.(1)(3)(4)
C.(2)(3)(4)
D.(1)(2)(3)(4)