加快经济发展速度必须以
A．提高劳动生产率为前提B．增加国民收入为前提C．使国民生产总值提高为前提D．提高经济效益为前提
参考答案：D
She kept_____playing computer games the whole time, which resulted____her failure in the exam.
A．up; from
B．on; from
C．up; in
D．on; in
α、β表面污染仪器的效率是什么？
