十一届三中全会以后，率先改革的是[ ] A．城镇 B．沿海地区 C．农村 D．大

一患者出现自发性疼痛，牙龈发炎，出血。X线片显示龈壁部分充填物位于牙体组织外：从X线片中可以推测导致患者出现自发性疼痛，牙龈发炎，出血的最可能原因是（）

A.继发龋

B.牙周炎

C.咬合早接触

D.充填物悬突

E.第三磨牙阻生

把下列句子中的从句改为不定式短语。

1. There are still a lot of difficulties we have to overcome.

    ________________________________________________________________________________

2. Before the machines leave the factory, there is a series of tests that must be passed. 

    ________________________________________________________________________________

3. At the end of the speech he expressed the desire that he should come and work in China someday. 

    ________________________________________________________________________________

4. They signed an agreement that they should expand the trade between the two countries. 

    ________________________________________________________________________________

5. The commander gave orders that we should cross the river.

    ________________________________________________________________________________

6. She was excited when she heard the news. 

    ________________________________________________________________________________

7. I'm glad I have seen your mother.

    ________________________________________________________________________________

8. The mother was pleased when she saw her son doing so well at school. 

    ________________________________________________________________________________

9. He was very happy when he saw us so happy. 

    ________________________________________________________________________________

10. They will be disappointed when they hear it. 

    ________________________________________________________________________________

我国流行性出血热主要的传染源是

A．人

B．人和褐家鼠

C．人和黑线姬鼠

D．黑线姬鼠和褐家鼠

E．大林姬鼠

一头驴子背盐渡河，在河边滑了一跤，跌在水里，盐溶化了。驴子站起来时，感到身体轻松了许多。驴子非常高兴，获得了经验。后来有一回，它背了棉花，以为再跌倒，可以同上次一样，于是走到河边的时候，便故意跌倒在水中。可是棉花吸水，驴子非但不能再站起来，而且一直向下沉，直到淹死。最适合作这段文字标题的是（）。

A.过河的驴子

B.盐与棉花

C.愚蠢的驴子

D.驴子的经验

维生素E含量丰富的食品是()

A．水果

B．植物油

C．蛋类

D．肉类

E．蔬菜