Dad _____ lunch at home. [ ]
A. isn't has
B. doesn't has
C. don't have
D. doesn't have
答案:D
等离子弧焊喷嘴孔径和孔道长度,应根据焊件金属材料的种类和厚度以及需用的焊接电流值来决定。( )
凡十一脏皆取决于()。
A.肺
B.心
C.肾
D.肝
E.胆