问题 单项选择题

血沉升高见于以下疾病,除了()

A.多发性骨髓瘤

B.妊娠期

C.SLE

D.真性红细胞增多症

E.严重贫血

答案

参考答案:D

解析:血沉能预示某些疾病发展和判断预后,凡体内有感染或组织坏死,或疾病向不良性进展,血沉一般会加快。妊娠期血沉增快可能与生理性贫血、纤维蛋白原量逐渐增高、胎盘剥离、产伤等有关。多发性骨髓瘤、巨球蛋白血症时,浆细胞的恶性增殖致使血浆病理性球蛋白高达40~100g/L或更高,血浆纤维蛋白原或球蛋白增多,致使红细胞zeta电位降低,彼此易于沾边成缗钱状,此种聚集的红细胞团块与血液接触的总面积缩小,受到血浆的阻力减弱而使血沉加快。轻度贫血对血沉尚无影响,若血红蛋白低于90g/L时,血沉可因此而增快,贫血越严重,血沉增快越明显,乃因红细胞数量稀少,下沉时受到的摩擦阻力减少等所致。反之,红细胞增多症的血沉减慢,红细胞形状对血沉也有一定影响,红细胞直径愈大,厚度愈小,血沉愈快。而球形红细胞不易形成缗钱状,所以血沉缓慢。

阅读理解

阅读理解

      Imagine this: a television screen has the size and thickness of a piece of paper. You carry it around in

your pocket and take it out when you want to watch a show. Imagine a guitar so tiny that you can't see it

with the human eye, but you can hear sound when its strings are pulled.

      Nanotechnology (纲米技术)  is the science that deals with doing things in a very small way, and it is

being studied and developed all over the world. Many scientists say nanotechnology will produce the next

industrial revolution (工业革命) .

      Perhaps nanotechnology will have the biggest influence on medical science. Imagine manobots (纲米机器人) in medicine. Thousands or even millions of tiny machines can be sent into the human body with

specific tasks. For example, they can be designed to find and destroy cancer cells or viruses (病毒). Other machines may stay in the human body for ever to help organs (器官) that are not working properly.

      When could all of these happen? Scientists predict that most of these are possible in the next 30 years. Thousands of scientists around the world are working on these micro - machines.  Nanotechnology is just around the corner.

1. The two examples in Paragraph l are used to __________            

A. introduce the smallest television            

B. introduce a new kind of guitar            

C. introduce the topic of the passage

2. Nanotechnology ___________            

A. will cause an industrial revolution            

B. deals with things in old ways            

C. has studied the whole world

3. The underlined word "they" in the third paragraph refers to (指代)________            

A. scientists          

B. human bodies            

C. tiny machines

4. The tiny machines _____________          

A. are too small to be repaired            

B. can be put in a human body to kill viruses            

C. may not work well in a human body

5. The underlined phrase "around the corner" in the last sentence means"_________"          

A. far away  

B. at present      

C. in the near future

选择题