电动吸引器吸痰时,如一次不能将痰吸尽需让患者休息多少分钟后重吸痰液()。
A.0.5~1min
B.2~3min
C.4~5min
D.6~8min
E.9~10min
参考答案:B
A.乙烯、乙炔、l,3一丁二烯都能发生加聚反应
B.在核磁共振氢谱中能出现两个峰
C.的名称:2,3-二甲基-4-乙基己烷
D.石油裂解和油脂皂化都是高分子生成小分子的过程
Most families in China now have only one child. Parents should teach their
children _____ others when they are young.[ ]
A. what to play with
B. when to get on with
C. which to play with
D. how to get on with