There is a famous English saying "You are what you eat", and it means what you put in your mouth will become part of you. Many experts（专家） use it to tell people it's important to have a good eating habit. For example, too much sweet food makes a person overweight. To avoid being fat, kids are told to keep off sweet food. However, a team of American scientists have discovered something new about eating sweet food.
"When we say some people 'sweet', we mean they are kind and friendly to us. Perhaps this word can help us learn more about people's feelings and acts." said Brian Meier, a scientist from the study team. "Taste is something we experience every day. What we have done is to find whether we can know someone's character and behavior depending on their taste."
In one of their experiments, college students were asked questions about their character- whether, for example, they were soft-hearted or not. Then they were asked to make a list of their favorite food. According to their answers, the scientists found that the students who liked sweet food were nicer.
In their another experiment, the scientists found that people who preferred sweet food such as cookies and chocolate were more willing to help other people in need, and those who ate non-sweet food such as chips weren't. For example, people with a sweet tooth were more likely to volunteer to clean up their city, visit sick children in the hospital and so on.
The result of the experiments is that people's helpfulness or being nice has something to do with their taste for sweet food. So eating sweet food is a useful way to make people nice and helpful. Next time, try some ice-cream.
The underlined word "it" in the sentence "Many experts use it to tell people it's important to have a good eating habit." refers to______.

A．the sweet food	B．the English saying
C．the American team	D．the eating habit

According to the result of the experiments, sweet food makes people______.

A．overweight

B．excited

C．relaxed

D．friendly

The scientists found that the people who preferred______ were less helpful.

A．chips

B．chocolate

C．ice-cream

D．cookies

It can be learnt from the passage that______.

A．scientists asked college students questions about their future

B．scientists told college students not to eat sweet food

C．people with a sweet tooth are more willing to help others

D．people's character has nothing to do with their taste