问题 选择题

人体免疫有三道防线,在这三道防线中,属于非特异性免疫的是        (  )

A.只有第1道防线

B.只有第2道防线

C.1、2两道防线

D.1、3两道防线

答案

答案:C

题目分析:第一道防线是由皮肤和黏膜构成的,它们不仅能够阻挡病原体侵入人体,而且它们的分泌物(如乳酸、脂肪酸、胃酸和酶等)还有杀菌的作用,呼吸道黏膜上有纤毛,具有清扫异物的作用;第二道防线是体液中的杀菌物质--溶菌酶和吞噬细胞(如白细胞),具有溶解、吞噬和消灭病原体的作用;人体的第三道防线主要是由免疫器官和免疫细胞组成,病原体侵入人体后,刺激淋巴细胞产生抗体。免疫分为两种,一种是非特异性免疫,是指人生来就有的,对多种病原体有防御作用,另一种是特异性免疫,是出生后逐渐建立起来的,只针对某一特定的病原体或异物起作用,其中第一道防线和第二道防线为人体的非特异性免疫,第三道防线属于特异性免疫。皮肤的屏障作用,属于第一道防线;溶菌酶的杀菌作用,白细胞的吞噬作用属于第二道防线,这些免疫都是人生来就有的,对多种病原体都有防御功能,故属于非特异性免疫;接种卡介苗后人体会产生抵抗结核杆菌的抗体,人体就不会再得结核病,这种免疫是后天获得的,只针对某一特定的病原体结核杆菌起作用,属于特异性免疫。

点评:此题为基础题,解题的关键是知道非特异性免疫是先天性的,包括人体的第一和第二道防线,而特异性免疫是后天性的,主要指人体的第三道防线。

阅读理解

阅读理解。

     Positive thinkers admit when they feel frustrated (受挫折的) or depressed, they don't ignore it.

But they don't blame themselves either. Instead, they try to understand the negative thoughts and

feelings and counter (反击) them with more positive ones.

     So how do you stay positive, maintain motivated and sustain (保持) healthy behaviors? Here are

some tips:

     Look for a good role model. There is always someone who seems to be doing just what you want

to be doing. Maybe they've scheduled exercise into their workday and switched from coffee to green tea.

Learn from a successful friend, family member or colleague. Ask them how they keep healthy and follow

in their footsteps.

     Try some positive self-talk and avoid negative-talk. Take a minute to give yourself an ego boost. Repeat

some motivational words out loud to yourself. Negative talk such as"I can't do it," "I'm fat," is dangerous

for your well-being and healthy goals. Try to avoid the negative self-talk before it harms you. Remind

yourself that you deserve happiness and can make positive changes.

     Get support. Tell your friends and family about your healthy habits. It helps to have an encouraging

network.  

     Reward yourself. Treat yourself to something for your healthy efforts. Take a nice bath, get a massage,

and enjoy a new DVD or CD.

     Have a plan. Making a plan to exercise or eat healthy lunches with a friend can mean the difference of

sticking with your goals or falling off track. If you've planned for an activity, you'll likely stick with it.

You may even find that writing down your goals and steps to achieve them can help you stay on track.

Take it day by day or week by week. The process of writing down your personal action plan is a good

way to keep you honest and watch your progress or failures.

1. By writing the text the author intends to _______.

A. offer some advice on how to stay positive

B. persuade readers to learn from a role model

C. provide some solutions to personal problems

D. inform readers of some tips on physical health

2. What does the phrase "to give yourself an ego boost" in Paragraph 4 mean?

A. to get lost in deep thought.

B. to think about the hardships.

C. to check what mistake you made.

D. to make you feel better about yourself.

3.Which of the following would the author Not agree to?

A. Saying some positive words to yourself helps you to feel good.

B. By staying with your companion you can avoid the negative-talk.

C. A successful friend, relative or colleague can be your role model.

D. Creating a helpful network is a good way to keep you motivated.

4.To make sure that you always stay on track, what should you do?

A. Eat out with your best friends.

B. Relax yourself after a hard day. 

C. Write down what you want to achieve

D. Modify your plans as often as you can.

单项选择题