在双膜理论中,气体通过液膜的推动力为(),通过气膜的推动力为(),阻力主要来自()。
参考答案:浓度梯度,分压梯度,液膜
细菌的繁殖方式是( )
A.出芽
B.孢子生殖
C.有丝分裂
D.有性繁殖
E.无性的二分裂
You had better encourage your children to____some of their pocket money for future education .
A. put aside
B. put up
C. put off
D. put back