阅读理解。

    You're sitting on the train home and the person opposite you yawns (打哈欠). Suddenly, you're yawning

with him, though you're not tired.

     This phenomenon confused scientists for years until a recent study found that people tend to sympathize

with fellow humans. Supporting this claim was the discovery that those children who were unable to form

normal emotional ties with others did not experience contagions (有感染力的) yawning, which showed that

humans communicate regularly without words.

     Hogo Critchley, a neuroscientist, has conducted an experiment recently, which will prove that happiness

and sadness can spread like the common cold. According to Critchley, our mind and body are in constant

exchange about how we're feeling. "Emotions are closely linked with states of internal (内部的) responses,"

he explained. "There are also more visible changes in our gesture and facial expressions. When we're in a

group, these signals can spread to another person. For example, there're the obvious tendency to smile when

smiled at and there are less obvious changes that reflect emotions of surprise, anger or sadness such as a

change in our heart rate and blood pressure."

     Hugo Critchley further explained, "Our bodies synchronise and when we like the other Person, we even

copy his behaviour. Next time you chat with a friend, take note of how you're sitting-it's pretty likely that

you will be the same. Scientists believe it's our way of telling each other that you're parents. Through body

language, humans give each other very subtle (微妙的) but clear signals that show emotions."

     So, what lessons can we learn from this? "spend time with happy people-otherwise your health could

suffer," said Critchley. "When we're sad, our body goes into fight or flight mode. But when we're happy, our

body works normally and we feel relaxed and positive. So we look bright, our skin glows, we feel healthy and

it affects everyone around us."

1. According to Hugo Critchley, _____.

A. emotions are as visible as facial expressions

B. we yawn more frequently when we have a cold

C. emotions are connected with states of internal responses

D. the change of blood pressure is not linked with the change of emotions

2. The underlined word "synchronise" in paragraph 4 means "_____".

A. move slowly

B. change rapidly

C. relax temporarily

D. respond accordingly

3. From the passage we can learn _____.

A. sadness is as contagious as happiness

B. anger is less contagious than friendliness

C. surprise is more contagious than smile

D. surprise is the most contagious among emotions

4. Which of the following statements is true according to the passage?

A. Emotions have delicate influence on fellow humans.

B. Children like copying the actions of the fellow humans.

C. Scientists are still confused about contagious yawning.

D. People tend to communicate more with body language.