接触粉尘作业，呼吸防护用品选择最常见错误是选用（）.
A、纱布口罩
B、防尘口罩
C、防毒面具
参考答案：A
It's exciting to be a chairperson, but I'm _____ my ability to do all the extra work. [ ]
A. looking about
B. learning about
C. quarrelling about
D. worrying about
针刺时，针身与皮肤表面呈45°角倾斜刺入称（）
A.直刺
B.斜刺
C.平刺
D.齐刺
E.扬刺
