放出移液管或吸量管中的溶液时，待溶液流完后管尖端接触瓶内壁约（）后再将移液管或吸量管移去。
A、5s
B、15s
C、30s
D、60s
参考答案：B
He is such a lazy man _______ nobody wants to work with ______. [ ]
A. that; /
B. as; him
C. whom; him
D. as; /
联系实际论述市场经济的“市场主体的自主性”特征。
