V型皮带每种型号的带长都有若干种，（）为公称尺寸，有标准规格。A.中心线长 B.外同

阅读短文，根据短文内容选择所给问题的答案。

Dear friends,

My name is Tony. I am English. I am twelve years old this year. I am tall, and I am good at playing football. I am in Grade Seven. There are thirty boys and twenty girls in my class. We are learning Chinese in our school. Our Chinese teacher is Mr. Wu. He is a little short, but he is very strong. He is very nice to us. I have some good friends in my class. Tom is a tall boy and has short black hair. He is good at playing football, too. Alice is short and she loves wearing red dresses. She is good at English. Shelly has long hair. She can speak Japanese and she likes swimming. We all study hard.

What about your school and your friend?  Please write soon.

Yours,

Tony

小题1:Which country is Tony from?

A．America.

B．England.

C．China.

D．Japan.小题2:Who is Mr. Wu?  

A．He is Tony’s English teacher.

B．He is Tony’s father.

C．He is Tony’s friend.

D．He is Tony’s Chinese teacher.小题3:How many students are there in Tony’s class?

A．50.

B．30.

C．20.

D．52.小题4:Who likes swimming?

A．Tom.

B．Alice

C．Shelly.

D．Mr. Wu.小题5:Who writes this letter?

A．Tony

B．Tom.

C．Shelly.

D．We don’t know.

依据“观察小鱼尾鳍内血液流动”实验，回答：

（1）在实验中用湿棉花包住鱼头部的目的是保持鱼______的湿润，维持鱼______作用的进行．

（2）右图是在显微镜下观察到的小鱼尾鳍内的一总分血管的分支情况和血流情况图，由此可知：①是______；③是______；②是______，判断的依据是______．

对于新增污染源非正常排放，需预测的计算点有（）。

A.环境空气保护目标

B.区域最大地面浓度点

C.区域最远地面距离

D.网格点

直流正极接地有造成保护_________的可能，直流负极接地有造成保护_________的可能。

消费者在储蓄与消费之间进行选择，主要依据的利率是（）

A.名义利率

B.实际利率

C.基准利率

D.官方利率