联苯胺生产厂工人好发（）
A.肺癌
B.膀胱癌
C.间皮瘤
D.阴囊癌
E.胃癌
参考答案：B
Mr.Black works in a restaurant. He is often very because there are
always lots of things to do. [ ]
A.free
B.dangerous
C.be
D.busy
干气密封使用的注意事项？
