题目内容：

    If you give money to a stranger on the street, does that make you a nice person? Do you always offer to help someone struggling with heavy bags? Do you often donate blood?

You may consider yourself to be a nice person, but you're probably not as nice as you think.

This is a new study carried out by professors from the University of London. The study looked into whether there is a connection between nice people and their levels of health, wealth and happiness. During the study, participants（参与者）were given a list of "nice" activities and asked which ones they often do. The result was surprising-98 percent of us consider ourselves to be among the nicest 50 percent of the population.

"In most cases, people think of themselves as nice, but it is not as simple as that," study leader Jonathan Freeman told.

The most common practices were giving directions to strangers, holding doors open and giving up seats on public transport. However, 3/4 said that they rarely helped people carry heavy shopping bags, and only 1/6 often gave money to strangers. Just 1/4 donated blood often or helped someone cross the road.

Though our thoughts of ourselves didn't match up with scientific research, this nicer than-others thought, according to Freeman, may actually do good to us. In the study led by Freeman, those who thought themselves as "nice" were likely（可能的）to be richer, healthier and happier. "Nice" people are almost three times more satisfied with their lives and make more money compared to the "not very nice" participants.

"Our study shows that participants who report that they are 'nice' scored higher on emotional intelligence（情商）, and it can help them deal better with stress and troubles in their lives," Freeman told The Independent.

1.What does the article mainly talk about?

A."Not very nice people" must be unhappier.

B.Nice people must be richer and happier.

C.Nice people may be happier than the "not very nice".

D.The "not very nice" may be wealthier than nice people.

2.What's the main idea for Paragraphs 3, 4 and 5?

A.People are probably as nice as they think.

B.A new study about nice activities was carried out.

C.Most people consider themselves to be nicer than others.

D.People's thoughts of themselves didn't match up with scientific research.

3.According to the study, which of the following is WRONG with the participants?

A.Most of them always thought of themselves nice.

B.Only one in seven often gave money to strangers.

C.They sometimes offer to help someone struggling with heavy bags.

D.Just a quarter donated blood often or helped someone cross the road.

4.What does the underlined word "it" in the last paragraph refer to（指的是）?

A.The study. B.The stress.

C.Being nicer to others. D.Having higher emotional intelligence.