矿井中H2S的最高允许浓度为()。
A.40ppm
B.2.5ppm
C.5ppm
D.6.6ppm
参考答案:D
— Whom shall I give the document?
— To ________ is in the office. However, _______to require a written paper for it.
A.whom; make sure
B.who; make sure
C.whomever; be sure
D.whoever; be sure
简述成果考核法的基本内容及其优缺点?