关于血浆因子亚基抗原测定说法不正确的是（）。 A.需要含有Fα亚基和β亚基抗血清的琼

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

1. Which country is Tony from?

A. America.    

B. England.    

C. China.      

D. Japan.

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.

3. How many students are there in Tony's class?

A. 50.        

B. 30.          

C. 20.        

D. 52.

4. Who likes swimming?

A. Tom.        

B. Alice        

C. Shelly.   

D. Mr. Wu.

5. Who writes this letter?

A. Tony      

B. Tom.    

C. Shelly.    

D. We don't know.

常用于肿瘤正电子发射计算机断层显像（PET）的显像剂是（）。

A.¹¹C-CO₂

B.¹⁸F-FDG

C.¹⁸F-NaF

D.¹⁵O-H₂O

E.¹³N-尿素

用里脚手架砌筑突出墙面（）mm以上的屋檐时，应搭设挑出墙面的脚手架进行施工。

除钙镁反应2小时后，发现钙镁含量仍未达标，该如何处理？

什么是环境？如何分类？