砧木依繁殖方法分为()和()。
参考答案:实生砧木、无性系砧木
--- My mother has a cold today, and I have to take care of her.
--- .
A.Thank you
B.Oh, I don’t know
C.I’m sorry to hear that
D.That’s Ok.
小儿肺炎最主要的发病机制是
A.缺氧
B.酸中毒
C.毒血症
D.水钠潴留
E.二氧化碳潴留