article: Saying no starts small
  'All right then-just one more piece...' Words every girl has said when they are faced with the delicious cheesecake. Of course, many of us know we may eat the whole thing in the end.
  It isn't just girls. Most of us find it hard to say 'no' to something attractive, However, scientists now say that willpower is very important to success and a happy life.
  Scientists in different countries have been studying the effects of willpower on people's lives for a long time. The results are similar, according to an article on February 7 in the Guardian, a famous British newspaper.
  In one experiment, scientists told young children that they could either have a marshmallow  now, or two marshmallows in 15 minutes. Waiting obviously needed more willpower. Scientists then continued studying the children as they grew up. They wanted to see if some children always had stronger willpower. They also wanted to see how having stronger willpower affected their lives.
  Years later, scientists found that the children who had waited for two marshmallows were all healthier, happier and richer adults. Oppositely, the children who had shown weaker willpower at that young age were more likely to be in low-paid jobs, to be overweight, to have social problems.
  But there is hope, Roy F Baumeister, an American social psychology  professor  told the Guardian. Baumeister says we can train our willpower just like we train our muscles.  Even a little practice can strengthen our overall self-control if we do it regularly.
  You could start by making yourself stand up straight, speaking in complete sentences, or using a computer mouse with the other hand. Scientists have found that people who manage to change little habits often perform much better in laboratory willpower tests.
  Like muscles, willpower can 'get tired'. Don't try to do too many things at the same time, or when you don't have enough energy, for example when you are ill.  If you already feel tired, you can try to recharge  your willpower with a good night's sleep and by eating well.
question: What can we infer from the experiment?
options: The scientists had already known the results before the experiment. It showed that willpower is the most important to success and a happy life. The children who chose to wait were more likely to be successful in their lives. The children who chose only one marshmallow at first had stronger willpower.