生胶随温度的变化有三态，即（）态、（）态和（）态。

下列离子方程式与所述事实相符且正确的是[ ]

A．用硫氰化钾溶液可以检验溶液中的Fe³⁺：Fe³⁺＋3SCN^-＝Fe(SCN)₃↓

B．用稀氢氧化钠溶液吸收二氧化氮：2OH^-+2NO₂＝NO₃^-+NO↑+H₂O

C．水杨酸()与足量的Na₂CO₃溶液混合：

D．向氯化银悬浊液中滴加氨水：2NH₃·H₂O+AgCl＝Ag(NH₃)₂Cl + 2H₂O

收款人根据购销合同发货后委托银行向异地付款人收取款项，付款人向银行承兑付款，这种结算方式称为( )结算方式。

A．委托收款

B．信用证

C．汇兑

D．托收承付

句型转换。

1. Mr. Li began to teach English in this school in 1999. (同义句转换)

    Mr. Li _______ ________ English in this school since 1999.

2. Our monitor has been a League member for two years. (同义句转换)

   Our monitor ________ the League two years ago.

3. My grandpa had to collect water from the village well. (改为反意疑问句)

   My grandpa had to collect water from the village well, _______ ________?

4. They can hardly believe it. (改为反意疑问句)

    They can hardly believe it, _______ _______?

5. He spent hours cleaning out the refrigerator. (同义句转换)

   He _______ hours _______ _______ out the refrigerator.

刮板式清扫器的清洁面与胶带的接触面积的最低限度是多少？

下列哪项属于肝内管道系统（）

A.下腔静脉

B.门静脉

C.肝静脉

D.肝动脉

E.肝内胆管