Please put this hat ___________![ ]
A. in
B. on
C. at
答案：B
可引起农民肺的粉尘是
A．棉、麻等植物性粉尘B．田间飞扬的粉尘C．谷物类粉尘D．霉变枯草粉尘E．飞扬的人、畜粪粉尘
