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 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.

【小题1】The function of Paragraph 1 is to_________ .

A．introduce the topic of the passage	B．give an example
C．make an argument	D．show the main idea of the passage

【小题2】Most genetic changes happen because of___________ .

A．people’s condition at birth	B．environmental pollution
C．people’s bad living habit	D．heart disease and cancer

【小题3】The underlined word “it” in Paragraph 5 refers to__________ .

A．the footprint	B．the cement
C．the harmful effect	D．the genetic change

【小题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 offer evidence that a damaged gene can heal itself.

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

I travel a lot, and I find out different “styles”（风格）of directions every time I ask “ How can I get to the post office?”
Foreign tourists are often confused（困惑的）in Japan because most streets there don’t have names. In Japan, people use landmarks（地标）in their directions instead of street names. For example, the Japanese will say to travelers, “ Go straight down to the corner. Turn left at the big hotel and go past a fruit market. The post office is across from the bus stop.”
In the countryside of the American Midwest, there are not usually many landmarks. There are no mountains, so the land is very flat. In many places there are no towns or buildings within miles. Instead of landmarks, people will tell you directions and distances. In Kansas or Iowa, for example, people will say, “ Go north two miles. Turn east, and then go another mile.
People in Los Angeles, California, have no idea of distance on the map. They measure distance in time, not miles. “ How far away is the post office?” you ask. “ Oh,” they answer, “ it’s about five minutes from here.” You say, “ Yes, but how many miles is it?” They don’t know.
It’s true that a person doesn’t know the answer to your question sometimes. What happens in such a situation? A New Yorker might say, “ Sorry, I have no idea.” But in Yucatan, Mexico, no one answers “ I don’t know”. People in Yucatan believe that “I don’t know” is impolite. They usually give an answer, often a wrong one. A tourist can get very, very lost in Yucatan!
【小题1】When a tourist asks the Japanese the way to a certain place, they usually _______ .

A．describe the place carefully

B．show him a map of the place

C．tell him the names of the streets

D．refer to recognizable buildings and places

【小题2】What is the place where people measure distance in time?

A．New York.

B．Los Angles.

C. Kansas C. Iowa
【小题3】People inYucatan may give a tourist a wrong answer ________ .

A．in order to save time	B．as a test
C．so as to be polite	D．for fun

【小题4】What can we infer from the text?

A．It’s important for travelers to understand cultural differences.

B．It’s useful for travelers to know how to ask the way properly.

C．People have similar understanding of politeness.

D．New Yorkers are generally friendly to visitors.