管孔内径大的管材应放在管群的什么位置（）。 A.内侧 B.外侧 C.上边 D.下边

阅读理解。

     Wearing the wrong type of glasses will do harm to your eyes. This is not true for adults, although

incorrect glasses may not be good for children under 10. Ready-made glasses, and not wearing when

you should, won't do harm to your eyes, but you may see better with glasses that are specially made for

you.

     Watching too much television is bad for your eyes. This is not true. People with easily affected eyes

may find they get red and aching from staring at a fixed distance for long periods, but there won't be

any lasting effects.

     Carrots will help you see in the dark. Carrots are rich in beta-carotene, which the body can change

into vitamin A, too little of which can cause night blindness. However, people in most countries don't

need to worry about vitamin A deficiency (缺乏), night blindness is more likely to be connected with

another vision problem.

1. According to the passage, which of the following is TRUE?

A. Ready-made glasses will do harm to one's eyes.

B. Wearing the wrong glasses may do harm to children's eyes.

C. The human body is unable to change beta-carotene into vitamin A.

D. Watching less television may do harm to children's eyes.

2. Night blindness is most likely caused by ______. 

A. staring for long periods 

B. too much beta-carotene 

C. not enough vitamin A 

D. vision problems 

3. According to the article, eye problems can be corrected by ______. 

A. wearing specially-made glasses 

B. performing eye exercises 

C. cutting back on television 

D. eating more carrots 

4. Watching too much television can cause ______. 

A. night blindness 

B. lasting eye problems 

C. a number of vision problems 

D. eye trouble for a limited time 

5. The main purpose of this article is to ______. 

A. tell people of the importance of their eyes 

B. tell people how to protect their eyes 

C. tell people to have more carrots 

D. tell people something more about their eyes 

受教育者应该履行的受教育的义务,下面哪项不是受教育的义务（   ）

A．认真履行按时入学的义务

B．认真履行接受规定年限的义务教育的义务，不得中途辍学

C．认真完成九年义务教育就可以

D．认真履行遵守法律和学校纪律，尊敬师长，努力完成规定的学习任务的义务

OMT 定义了三种模型来描述系统。 （49） 可以用状态图来表示； （50） 可以用数据流图来表示。 （51） 为上述两种模型提供了基本的框架。

（49）处填（）。

A．对象模型

B．功能模型

C．动态模型

D．类模型

史诗在它表层情节之后必然隐含了象征思想（）？

采用相当低的价格出售高质量的产品，属于（）

A.认知价值定价法

B.通行价格定价法

C.价值定价法

D.目标收益定价法