在生产环境中可吸入性粉尘的空气动力学等效直径为
A.<15μm
B.<12μm
C.<10μm
D.<5μm
E.<1μm
参考答案:A
— ________ the way, did you meet Danny ______ your way home yesterday afternoon?
— Yes, I did. [ ]
A. On; by
B. By; on
C. On; in
D. By; in
简述秘书参谋效应的含义及意义。