()不是Z525立式钻床的结构组成部分。
A.横梁
B.工作台
C.变速手柄
D.主轴变速箱
参考答案:A
You _____ feed you dog at table. [ ]
A. ought
B. ought not to
C. ought to not
D. don't ought to
什么是冻结法?