题目内容：

    If you’re riding in the car on the way home from school or soccer practice, does the sight of fast food restaurant signs make you hungry for a cheeseburger, some French fries or a piece of pizza?

Think about some of the signs for the most popular fast food restaurants. What do the signs for McDonald's, Wendy's, Burger King, Dairy Queen and Pizza Hut have in common? They all make prominent (突出的) use of two colors: red and yellow.

Could it be that these colors — red and yellow — make you hungry and want to stop for fast food? Although it might sound crazy, that's exactly what some scientists believe. The idea even has a name: the ketchup (番茄酱) and mustard (芥末) theory.

Scientists also point out that studies show that color gets communicated to the brain faster than any other type of communication. For example, experts believe that the color red inspires feelings of warmth, comfort and love. Similarly, yellow draws feelings of happiness, excitement and cheer.

Researchers believe that these colors, especially when used on fast food restaurant signs, create the perfect feelings to make us feel hungry and want to stop to eat.

Other scientists,however,disagree with the ketchup and mustard theory and point out that there isn't enough scientific data (数据) to support the theory. They think that feelings of happiness and excitement connected with the colors red and yellow aren't necessarily equal to hunger.

While the science of colors and their exact influence on us may be uncertain, it’s clear that fast food restaurants believe that in some way, it is good for them to include red and yellow on their signs. Do these colors make us hungry? Maybe ... or perhaps it’s our own happy memories of delicious cheeseburgers, salty French fries and ice- cold sodas that keep us coming back for more!

1.Why does the writer ask the question in Paragraph 1?

A.To know when people will feel hungry.

B.To ask people to take part in the research.

C.To get people into the topic of the passage.

D.To find what fast food restaurant sign is the most popular.

2.What common point do most fast food restaurants share?

A.They provide similar foods. B.Their foods are in red and yellow.

C.Their signs include red and yellow. D.Their foods are the favorite of people.

3.According to Paragraph 4, some scientists believe that ________.

A.people cannot refuse to enjoy fast food B.colors can make communication easier

C.people use colors to express their feelings D.colors have influences on our feelings

4.What can we learn from the last paragraph?

A.Colors are important to fast food restaurants. B.It’s uncertain whether colors make us hungry.

C.We need to study the science of colors. D.Delicious food can leave us good memories.