Question

Smoking is harmful. But as soon as you quit the habit, everything will be OK, right?

Wrong

New research has found that even if you give up smoking, the damage it has done to your genes(基因) will stay there for a much longer time. In the research, a team of US scientists studied the blood of 16,000 people. Among them, some were smokers, some used to smoke, and the rest were non-smokers. Scientists compared their genes and found that more than 7,000 genes of smokers had changed—a number that is one-third of known human genes.

According to NBC News, both heart disease and cancer are caused by genetic changes. Some people may have had the changes when they were born, but most people get them in their day-to-day lives while doing things like smoking.

When you stop smoking, a lot of these genes will return to normal within five years.

This means your body is trying to heal (治愈) itself of the harmful effects of smoking. But the changes in some of the genes stay for longer. They can stay for as long as 30 years. It’s almost like leaving a footprint on wet cement (水泥)—it will always be there, even when you’ve walked away and when the cement becomes dry.

Although the study results may make people unhappy, there is a bright side: the findings could help scientists invent medicine to treat genetic damage caused by smoking or find ways to tell which people have heart disease or cancer risks.

1.The function of Paragraph 1 is to ________.

A. show the main idea of the passage    B. give an example

C. make an argument    D. introduce the topic of the passage

2.Most genetic changes happen because of ________.

A. people’s condition at birth    B. people’s bad living habits

C. environmental pollution    D. heart disease and cancer

3.The underlined word “it” in Paragraph 6 refers to ________.

A. the genetic change    B. the cement

C. the harmful effect    D. the footprint

4.Which of the following statements is true?

A. The findings are the fruit of more than three years’ research.

B. The findings have prevented more people from starting smoking

C. The findings help to find cures for genetic damage caused by smoking.

D. The findings offer evidence that a damaged gene can heal itself.

Answer

1.D

2.B

3.D

4.C

【解析】根据最近的调查研究发现，由于吸烟而引起的基因突变，在戒烟后并不会马上消失，而是会在体内保留一段时间，这些基因突变大部分会在五年内恢复正常，但有一些甚至三十年都不会恢复。虽然这样的调查结果让大家有些担忧，但是这也有助于科学家发明一些治疗药物，或是指出哪些人有患心脏病或癌症的危险。

1.结构分析题。根据“Smoking is harmful. But as soon as you quit the habit, everything will be OK, right? Wrong.”可知，第一段提出了这样一个问题“吸烟是有害的，但是只要你戒烟，一切都会恢复正常，对吗？”“并不是”，接着下文便从一些调查研究的结果开始解释这个问题，文章围绕这一问题展开，所以第一段的作用是引出本文的主题，故选D。

2.细节理解题。根据第三段“Some people may have had the changes when they were born, but most people get them in their day-to-day lives while doing things like smoking”可知，一些人的基因突变是生下来就有的，但大部分人的基因突变是由于日复一日的做一些（有害身体的）事，比如吸烟，而积累下来的。故选B。

3.指代推测题。根据“It’s almost like leaving a footprint on wet cement (水泥)—it will always be there, even when you’ve walked away and when the cement becomes dry.”可知，它就像在水泥上留下的脚印——即使你把脚抬开了，当水泥变干的时候，它将一直留在那里，所以“它”指的是留在水泥上的东西，即脚印，故选D。

4.细节理解题。根据最后一段中“the findings could help scientists invent medicine to treat genetic damage caused by smoking.”可知，这些发现有助于科学家发明用于治疗由于吸烟引起基因破坏的药物。故选C。