问题 单项选择题

某二倍体动物的某细胞内含有10条染色体、10个DNA分子,且细胞膜开始缢缩,则该细胞()。

A.处于有丝分裂中期

B.正在发生基因自由组合

C.将形成配子

D.正在发生DNA复制

答案

参考答案:C

解析:

C。解析:此时细胞内10条染色体和10个DNA分子,没有染色单体,即DNA未复制,且细胞开始缢缩.则应处于分裂的末期。

阅读理解

阅读理解。

     It is common and usual to see people freak out when they face challenges in their life. We all

pass in different life problems and challenges. No one is free of life problems. Only a dead man

faces no problem. As long as you are alive, challenges are everywhere.

     How do you face problems and challenges in your life? Problems and challenges are the building

blocks of your personality. They make you who you are. Besides, whether what happened in your

life builds or destructs you depends on how you look at it. If you take your problems as troubles,

they will be troubles and may cause destruction. If you take them as constructive tools, you are going

to be built up on them.

     Problems are everywhere. No one can avoid them. And they are good too. They open up a

different look and opportunity if you are willing to see. When you face troubles, do not frustrate or

freak out. Just cool yourself to think in a different direction. Think in a positive way. Every problem

has its own good as well as bad sides. Focus on the good one. Look at the bright side.

     Besides, there is always a good person, perhaps your mom or dad, or one of your friends, right

beside you who can turn everything into your best if you are willing to turn to them. No matter what

happens, they will be there to help you. Trust them and they will never let you down. All you need

to know is that you are loved wherever you are.

1. What's the meaning of the underlined phrase "freak out" in Paragraph 1?

A. Feel shy.    

B. Stay calm.  

C. Keep up.    

D. Feel upset.

2. In Paragraph 2, the writer implies that ______.

A. problems cause troubles  

B. attitude is everything

C. challenges can be avoided  

D. personalities are built on failures

3. According to the last paragraph, when we're in trouble, we ______.

A. can only depend on our parents      

B. are not alone

C. should only believe ourselves        

D. are not confident

4. What's the writer's purpose to write the passage?

A. To encourage.  

B. To compare.  

C. To prove.

D. To explain

单项选择题