( )是一种孔加工机床,可用来钻孔、扩孔、铰孔、镗孔以及刮平面、攻螺纹等多种形式的加工。
A.钻床
B.电焊机
C.铣床
D.磨床
参考答案:A
—Such a mistake could have been avoided.
—Unfortunately, he _______ the mistake again and again.
A.repeated
B.would repeat
C.had repeated
D.would have repeated
我国对美、日输华货物木质包装主要关注的有害生物是松材线虫。