下列哪项是预防烧伤后肺栓塞的最主要临床措施
A．卧床
B．吸氧
C．止痛
D．抗凝
E．镇静
参考答案：D
As far as many parents are concerned, what a child should do,________, is to do well in his studies. [ ]
A. in all
B. above all
C. after all
D. at all
两个数的商是45，如果把被除数和除数都缩小5倍，商是 [ ]
A. 45
B. 9
C.不能确定
