琥珀胆碱用量达下列多少以上可通过胎盘进入胎儿体内()
A.50~1OOmg
B.110~150mg
C.160~200mg
D.210~250mg
E.260~300mg
参考答案:E
声音是由发声体的而产生的。钢琴、吉他、笛子等乐器发出的声音,即使音调、响度都相同,也可以从它们的__________来分辨。
The firemen _____ the fire as soon as they got to burning buildings.[ ]
A. put up
B. put away
C. put out
D. put down