简述影响插条扦插因素。
参考答案：
（1）内在：树种遗传特性、母树及枝条年龄、枝条部位和发育状况
（2）外界：土壤温度、土壤水分、空气湿度、插壤、光照
情景对话，选择正确句子补全对话。
A. Do you like these white socks?
B.May I help you?
C.How much is this pair?
D. Do you have other colours?
E.I'll take two pairs.
A: Good afternoon!
B: Good afternoon!
A: 1.__________
B: Yes.I want to buy some socks.
A: 2.__________
B: Sorry.I don't like white.3.__________
A: Yes.Here are red and black socks.
B: I want these black socks.4.__________
A: Five dollars.
B: OK. 5.__________
A: Well.Here you are.
晕厥常发生于（）。
A.二尖瓣狭窄
B.二尖瓣关闭不全
C.主动脉瓣狭窄
D.主动脉瓣关闭不全
E.三尖瓣关闭不全
