鉴别再生障碍性贫血和白细胞减少型白血病的主要检查是（） A.全血细胞减少 B.外周有

根据文章内容，判断正（T）、误（F）。

     Are you an impolite student? I hope your answer is "no"! What can you do to be a polite student? Have

you ever had these impolite behaviors?

     a. Do you usually play loud music in the evening?

     b. When you see the food you like, but there're many people waiting in line to buy it, will you cut in line?

     c. When you are eating food On the street, will you throw it on the ground?

     d. If you order a pizza half an hour ago, but it hasn't arrived yet, will you get annoyed?

     Manners are taught as soon as children can understand what parents are talking about. Maybe your father

and mother have told you thousands of times about what you should do and what you should not do. For

example, your parents told you that you shouldn't interrupt (打断) when your parents are talking.

     In some western countries, the first manner the children should learn is to make themselves clean. Parents

believe that keeping children clean is really important. Whether the children are at home or school, parents will

always tell them not to throw things at will (随意地).

( )1. It is OK to play loud music in the evening.

( )2. Manners are about what you should do and what you should not do.

( )3. It's impolite to cut in line when there are many people waiting in line to buy some food.

( )4. In Western countries, you can throw things at will when you are at home.

( )5. In the writer's opinion, if you want to be a polite student, you shouldn't have the four impolite behaviors.

下列关于显示器场频的描述，错误的是______。

A) 场频就是显示器的视频带宽
B) 场频=视频带宽／显示列数／显示行数
C) 场频越高，显示器的闪烁感就越强
D) 场频就是显示器的垂直扫描频率

β-萘胺主要损害（）

A.神经系统

B.循环系统

C.血液系统

D.消化系统

E.泌尿系统

以各州、各类型国家或各个国家在国际贸易额中所占的比重来表示的国际贸易指标是：（）

A、国际贸易额

B、国际贸易地利方向

C、对外贸易依存度

D、国际贸易商品结构

所谓天线的极化，就是指天线辐射时形成的电场强度方向，一般有（）、垂直极化。