问题 单项选择题

细胞核是细胞的重要结构。下列关于细胞核的叙述,正确的是()

A.核膜为单层膜

B.细胞核内有线粒体

C.细胞核内没有DNA

D.核孔是物质进出细胞核的通道

答案

参考答案:D

解析:核膜为双层膜;细胞核内没有线粒体,线粒体分布在细胞质基质中;DNA主要分布在细胞核内;核膜上有核孔,核孔是物质进出细胞核的通道。故选D考点:本题考查细胞核的相关知识。点评:本题意在考查考生的识记能力,属于容易题。

单项选择题
阅读理解

阅读理解。

     Recently a young fellow from Sheridan was accused of first-degree murder. The youth was

15 years old when he shot and killed a 79-year-old man while burglarizing (入室盗窃)the man's

home. The victim was a well-respected and much loved Sheridan citizen.

     The crime and punishment are tragedies. It was a tragedy that a wonderful citizen of the city

was shot and killed in his bedroom in the middle of the night. It is another tragedy that the young

man, now 17, will likely spend the rest of his life in prison.

     His mother had largely neglected the young man. Suffering an unhappy marriage life, his mother

sent him to live with an aunt and uncle in Sheridan. The youth really had no activities other than

skateboarding at the skate park.  The circle of friends that the youth had was basically in 1he same

boat: they had little parental love and care in their lives.

     I wonder what would have happened to the young fellow if he had been introduced to the joys

of the outdoors at an early age. Perhaps his life would have taken a different course. Many of us

have learned our outdoor skills by observing our parents, grandparents, aunts and uncles, or some

other adults. Basically, the people who taught us cared for us and wanted to get us interested in

their outdoor activities.

     Parents, grandparents, relatives, and friends of the family need to do the same thing today. We

need to educate our children in outdoor skills. We need to teach them by taking them fishing, hunting,

hiking, birding, horseback riding, and swimming. Most of all, we need to spend time with our children

and show them we care.

     We need to give our youths some healthy outdoor alternatives to the drug and troublemaking culture

that results from too little supervision and too little love. By doing so, perhaps we can avoid further

tragedies.

1. The purpose of the author in writing the article is ______.

A. to call for giving children outdoor experiences

B. to ask to punish children if they break the laws

C. to tell us a tragedy about a young boy

D. to present that too many troubles exist in society

2. What is the author's attitude towards the young fellow?

A. Hateful.      

B. Unconcerned.

C. Ironical.      

D. Sympathetic.

3. From the text we can know the reason for the young fellow's crime is that ______.

A. his mother didn't have a good marriage

B. his aunt and uncle treated him badly

C. he enjoyed skateboarding at the skate park

D. he was short of parental control and love

3. According to the fourth and fifth paragraph, we can know ______.

A. children used to do outdoor activities by themselves

B. parents are always playing with children

C. the boy may have avoided crime if taken care of

D. parents used to ignore their children