气体类危险化学品泄漏时,泄漏浓度()爆炸下限30%,可谨慎使用点方法。
A.不大于
B.不小于
C.大于
D.小于
参考答案:D
煤矿工人常见肺尘埃沉着病为
A.硅沉着病
B.煤矽肺
C.煤肺
D.硅酸盐肺
E.混合肺尘埃沉着病
I have a friend _______ would like to speak to you.
A.which
B.what
C.who
D.whom