问题 问答题 简答题

试述I型超敏反应的发生机制。

答案

参考答案:

致敏阶段:

(1)变应原①吸入性变应原②食物变应原③药物

(2)产生IgE抗体

(3)IgE与肥大细胞结合2.发敏阶段

(1)变应原与致敏靶细胞表面IgE结合

(2)致敏靶细胞和脱颗粒

(3)释放活性介质产生生物学效应①组胺\激肽原酶\嗜酸粒细胞趋化因子(ECF-A.②前列腺素\白三烯\血小板活化因子\细胞因子

阅读理解

These days, many students like playing 3Dgames. Do you know what 3D games are like? In most 3D games, game players need to control a character (人物). The character can be a robot or a soldier. Game players usually use the mouse to make the character move around in his own world. Game players can find things such as food and weapons to help them go on with the game. The character can go straight, sit down, turn left, turn right or pick up things in the game.

Some 3D games have many levels(等级). The character needs to finish different goals(目标) for each level. Game players can against their computers, and sometimes they can play with other players online(在线). It’s great fun to play 3D games. But playing 3D games for long is not good for our study.

小题1:In most 3D games, game players need to _______.

A.control a character

B.find a robot

C.act as a soldier

D.control the computer小题2:How do game players make the character move around?

A.By using the keyboard.

B.By using the mouse.

C.By telling the directions

D.By moving the computer.小题3:In the game, the character can _________.

A.go straight and sit down

B.turn left and turn right

C.pick up things

D.All the aboves.小题4:Which of the following is NOT true according to the passage?

A.Some 3D games have many levels.

B.The character needs to finish different goals for each level.

C.Game players can only play against their computers.

D.Game players can go online and play with other players together.

单项选择题