下列染毒途径中，吸收速度最快的为（） A.经消化道 B.经呼吸道 C.经肌内注射 D

已知关于x的方程（1-a）x²+（a+2）x-4=0，a∈R，求：

（Ⅰ）方程有两个正根的充要条件

（Ⅱ）方程至少有一个正根的充要条件．

词汇。

1. He is an h_______ boy, he never tells a lie.

2. He said that he p_______ the homeless people with some money.

3. The s_______ by the road said "No parking".

4. The company was e_______ in 1860.

5. He c_______ up with an idea to the problem and told us.

6. Only Tony didn't f_______ from that house while the earthquake took place.

7. It is important to dream, so _______ (坚持) your dreams.

8. I don't like to _______ (闲逛) in the street.

9. Picture story cartoons are very _______ (受人欢迎的) in the world.

10. People like to _______ (花费) many beautiful hours walking along the river.

扩展名为dbf的文件是（ ）。

A． 表文件

B． 表单文件

C． 数据库文件

D． 项目文件

先存款、后消费、不能透支的银行卡属于（）

A、借记卡

B、贷记卡

C、准贷记卡

D、信用卡

小腿的截肢理想部位是()

A．上1/4处

B．中1/3处

C．上1/5处

D．1/2处

E．以上均不对