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.

Ariana caught another whiff(难闻的味道) and tried to hold her breath. She moved away slightly, but Ashley only moved closer and continued talking. Ariana felt trapped. She wanted badly to tell Ashley that she didn't smell very good. But how could she do that without hurting her feelings? Instead, she gathered the remains of her lunch to throw in the trash, thankful for the excuse to get some fresh air. She looked back to see Ashley eating quietly. Ashley's hair was tangled(乱糟糟的) , and her clothes were dirty. Ariana forced herself to go back to the table and take her seat, vowing(发誓) that she would not sit with Ashley tomorrow.

When Ariana got home from school, she complained to her mother, ''There's a girl named Ashley who likes to sit next to me in school, but she smells bad. ''

''She's probably having a tough day, '' said her mother.

''No, it's not just one day. She smells bad a lot, '' Ariana explained. ''Nobody else likes to sit next to her, either. ''

''I don't think you understand Ashley's situation, so let me ask you this..., '' Her mother's tone was serious. ''Who makes sure that your hair is combed every morning so you'll look nice when you go to school? ''

''You do, '' answered Ariana.

''Who makes sure you're bathed and cleaned every day? And your clothes are washed and neatly ironed? ''

''You and Daddy, '' Ariana said again.

''Do you live in a nice home? Do you have enough to eat? ''

Ariana nodded, beginning to feel guilty. She was starting to understand now. Ashley couldn’t help her situation because she was only seven years old—the same age as Ariana. Grown-ups are supposed to take care of kids.

''Why doesn't her family take better care of her? '' Ariana asked.

''Not all children live in the best situation, '' her mother said. ''The best thing you can do for Ashley is to treat her with kindness and sympathy. ''

   Ask most people anywhere in the world what they want out of life and the reply will probably be“to be happy”. Ed Deiner，an American psychology professor，has spent his whole life studying what makes people happy，comparing levels of happiness between cultures and trying to find out exactly why we enjoy ourselves.

Many people would say that this question does not need an answer. But Professor Deiner has one anyway. “If you’re a cheerful，happy person，your marriage is more likely to last，and you’re more likely to make money and be successful in your job. On average，happy people have stronger immune systems（免疫系统），and there is some evidence that they live longer. ”

So who are the world’s happiest people？It depends on how the word is defined. There is individual（个人的）happiness，the sense of joy we get when we do something we like. But there is also the feeling of satisfaction we get when we know that others respect us and approve of how we behave. According to Professor Deiner，the Western world pursues individual happiness while Asia prefers mutual satisfaction.

“In the West，the individualistic culture means that your mood matters much more than it does in the East. People ask themselves if they are doing what is fun or interesting. They become unhappy when they can’t do any of these things. If you ask people from Japan or China whether they are happy，they tend to look at what has gone wrong in their lives. If not much has gone wrong，then they are satisfied. ”

“People from Spain and other Spanish-speaking countries have the happiest culture，”Professor Deiner found. “The biggest cultural difference is to do with pride and shame. Hispanic cultures report much more pride and much less shame than others. ”

Income（收入）also makes a big difference to people’s happiness，but only at the lowest levels. Average income earners in the US are much happier than people in poverty. But millionaires are only a little bit happier than people on average incomes. It seems that money makes us happy when we have enough to feel safe.

   What's the easiest way to stay warm in the super cold？【小题1】. At least that's what Santa Claus told me.

Over Christmas, Dennis and I went to Finland. We brought back some tips for keeping warm in a cold temperature.

Three layers（层）work wonders.

Start with the base layer, which sits right on your skin: choose something absorbent（有吸收力的）.【小题2】.

A sweater is a good choice. The most important layer is the outer clothes, which should be waterproof（防水的）and windproof.

【小题3】.

You lose heat from every millimeter of uncovered skin, which was the biggest lesson I learned on the trip. My whole body was well covered. But I missed one spot: my face. So it often felt like the wind was going to blow my nose off.

Exercise and don't just stand still.

When it's cold, exercising may be the last thing you feel like doing, but be smart.【小题4】. When we first got to Finland, we were freezing. But after a couple of minutes jumping around, we felt less cold.

Have a heater.

You may want to turn it on all the way up, but it's best to keep it between 18 and 20 degrees.【小题5】. Remember not to create a huge difference between inside and outside.