我国处理民族关系的原则是（     ）

Read and choose读句子，选择适当的词填空，把序号填在题前括号内。
a: Yes, we do.
b: This is our classroom.
c: Forty.
d: Your school is cool.
e: Where is the canteen?
 

A: Welcome to our school. ____ 

B: How many students are there in your classroom?

A: ____ 
B: Do you have a library?

A: ____ 

B: ____ 
A: The canteen is on the first floor. 

B: ​​____ 

—I've got a ticket to the ball game tonight.                        
—Oh. How ___________ you __________ it?

一粒种子，蕴含着世代相传的梦想。沈克泉为解决家乡人们吃油难问题，有了改良培育出产量高的油菜品种的梦想，乡亲们都嘲笑他“泥腿子想当科学家”，但他毫不在意，和儿子沈昌健经过艰辛努力，繁育的“贵野A”不育系获国家发明专利证书。这表明 (        )  

根据上图和实验现象，回答下列问题：（用化学式表示）