搜题请搜索小程序“爱下问搜题”
问题 单项选择题

自身免疫耐受，是在胚胎时期T细胞的分化过程中，其表面受体与胸腺中的APC表达的自身As-MHC复合物相互作用而被消除,这一过程是属于

A．阳性选择

B．阴性选择

C．T细胞克隆无能

D．B细胞克隆无能

E．基因缺陷

答案

参考答案：B

填空题

单词填空。

1. By 1881, the population of Ireland had ________ (减少) to 5.2 million.

2. China is getting more and more ________ (强大) in the world.

3. It is not allowed to _________ (打猎) wild animals in this area.

4. The climate ________ (影响) the amount of the rainfall last year.

5. A tiger is a very ________ (凶猛的) kind of animal. However, it won't attack you

   if you don't.

6. People say that barking dogs don't b________.

7. I'd a________ it if you let me get on with my job.
查看答案
单项选择题 B1型题

猩红热的临床特征为（）

A.发热3～4天后出疹，3～4天出齐，疹退后有麦麸样脱屑及色素沉着

B.发热1～2天后出斑丘疹，1～2天出齐，伴枕后淋巴结肿大，疹退后无脱屑或色素沉着

C.发热3～4天，一般情况好，热退后出斑丘疹，疹退后无脱屑及色素沉着

D.发热2～3天后出斑丘疹，皮疹稀少，伴疱疹性咽炎、肌痛，疹退后无脱屑

E.发热1～2天后出疹，呈鲜红色细小点状，疹间皮肤充血，伴咽痛，疹退后有脱屑
查看答案