浮游选煤常用捕收剂有()。
A、FP101
B、松油
C、杂醇
D、合成产品
参考答案:D
机械行业中的坍塌事故不包括( )。
A.爆破引起的坍塌
B.堆置物倒塌
C.挖沟时的土石塌方
D.建筑物坍塌
What’s the speaker going to do with the letter
A.He would throw it away.
B.He would keep it.
C.He would post it.
D.He would stick a stamp on it.