题目内容：

    We smile because we are happy, and we frown because we are sad. Recent studies suggest that our emotions are driven by their related facial expressions.

This February psychologists at the University of Cardiff in W ales found that people whose ability to frown is lessened by botox injections (肉毒杆菌注射) are happier, on average, than people who can frown. The researchers administered an anxiety and depression questionnaire to 25 females, half of whom had received botox injections to stop frowning. The botox injected people reported feeling happier and less anxious in general.

In a related study from March, scientists at the Technical University of Munich in Germany scanned botox injected people with FMRI machines while asking them to copy angry faces. They found that the botox subjects had much lower activity in the brain circuits (回路) involved in emotional processing and responses - in the amygdala, hypothalamus and other parts of the brain - as compared with controls who had not received treatment.

The concept works the opposite way, too. People who frown during an unpleasant procedure report feeling more pain than those who do not, according to a study published in May 2008 in the Journal of Pain. Researchers applied heat to the forearms of 29 participants, who were asked to either make unhappy, neutral or relaxed faces during the procedure. Those who exhibited negative expressions reported being in more pain than the other two groups.

No one yet knows why our facial expressions influence our emotions as they seem to. The associations in our mind between how we feel and how we react may be so strong that our expressions simply end up strengthen our emotions - there may be no evolutionary reason for the connection. Even so, our faces do seem to communicate our states of mind not only to others but also to ourselves. “I smile, so I must be happy,” Grob says.

1.What can we know about the result of the study from paragraph 2?

A.The ability to frown should be stopped by injection.

B.Less frowns make people happier.

C.Women love to frown and feel sad.

D.Half women have no ability to feel happy.

2.What did scientists do in the related studies?

A.They asked the participants to frown or smile.

B.They copied the expressions of the participants.

C.They asked the participants to stay negative.

D.They exposed the participants to heat.

3.What does the passage talk about?

A.Facial expressions influence our emotions. B.Facial expressions are driven by emotions.

C.Why people feel happy and frown. D.Botox injection is useful and meaningful.