E5015焊条通常采用的是( )。
A.交流
B.直流正接
C.直流反接
D.交、直流两用
参考答案:C
下列哪个不属于钩体病后发症()。
A.后发热
B.虹膜睫状体炎
C.反应性脑膜炎
D.肾损害
E.闭塞性脑动脉炎
—What's Tom doing?
—He is ______ his keys. [ ]
A. looking at
B. looking for
C. waiting for
D. working for