题目内容：

Here is a task for you: try to make as many kinds of facial expressions as you can. How many can you come up with?

Facial expressions are like a window to your emotions inside. Scientists used to believe that we only have six basic emotions-happy, sad, fearful, angry, surprised and disgusted-and ,therefore, each of our facial expressions falls into one of the six categories.

But it turns out that this is just the tip of the iceberg. In a recent study, scientists from Ohio State University, US, mapped 21 different facial expressions, more than tripling(是……的三倍) the original number, reported Science Daily.

Restricting emotions to just six categories is like “painting only using primary colors”, said Aleix Martinez, the lead researcher. He believed that human emotions are much richer than that, which is why he and his team decided to use advanced computer technology for further investigation.

In the experiment, scientists photographed 230 volunteers-100 male and 130 female-while they made faces in response to different words such as “you smell a bad odor(气味)”. They then closely studied the images by examining key muscles on volunteers’ faces, such as the corners of the mouth or the outer edge of the eyebrow, and finally identified 21 different expressions. These included what seem to be contradictory emotions such as “happily disgusted” and “sadly angry”, which scientists call “compound(混合的) emotions”.

Take “happily disgusted” as an example.” Putting on a happy face is usually done by drawing up the cheeks and smiling while a disgusted face often involves a scrunched-up(皱起的) nose and eyes. So the “happily disgusted” emotion created an expression that combined the smile of happy with the scrunched-up eyes and nose of disgusted. It was the emotion test subjects felt when something “gross(恶心的)” happened that was also funny-for example, when people spill(洒出) a lot of food on their clothes.

Similarly, “happily surprised” is an expression for receiving unexpected good news. “Sadly angry” is the face we make when someone we care about makes us angry.

According to Martinez, the researchers’ next step is to study the pathways and chemicals in the brain that activate(激活) and recognize those emotions. He believes that this could lead to effective treatments for people who suffer from conditions such as Post-Traumatic Stress Disorder(PTSD,创伤后应激障碍), which involves a lack of recognition of other people’s emotions.

1.The underlined part “this is just the tip of the iceberg” in Paragraph 3 probably means      .

A. this is a truth known to us all

B. this is the total amount of something

C. this is easily seen or discovered

D. this is only the smallest and most obvious part of something

2.How does the author explain the definition of “compound emotions” in the article?

A. With comparisons.

B. Through examples.

C. Through cause and effect analysis.

D. By presenting research findings.

3.According to the article, people are likely to become happily disgusted when      .

A. they receive unexpected good news

B. someone they don’t care about makes them happy

C. something unpleasant but also funny happens

D. they successfully escape from a dangerous situation

4.What can we conclude from the article?

A. There are several contradictory emotions we tend to overlook.

B. Females have more contradictory emotions than males do.

C. The chemicals in the brain that activate emotions are easy to identify.

D. Martinez’s next goal is to find an effective cure for people who suffer from PTSD.