题目内容：

Many people travel to different places in the world by air. Usually it takes a long time, perhaps half a day, for passengers to stay in the plan. So airlines（航空公司）offer passengers food. But it is common that they feel bad about food taste. Do you agree?

To solve this problem, airlines try hard to improve their food. They would like to do so because they don’t want to lose customers.

However, according to scientific research, part of the reason why plane food tastes bad is that at high altitude（海拔）we can not taste things as well as we do on the ground. Also scientists have found that our noses become very dry even before a plane takes off. As the plane moves up, the change in air  pressure（气压）reduces one third of the sensibility（感觉）of our taste buds（味蕾）. So our taste buds become senseless. The sad face, however, is that our noses don’t know it.

All of these help explain why food on the plane tastes so bad. They also help explain why airlines choose to offer passengers salty and spicy（辛辣的）food. Without doing so, the food would be tasteless.

Now there are many researches on this. According to one of them, some volunteers are asked to lie with their feet higher than their heads for weeks. And scientists write down their feelings about food taste.

Though scientists try their best, it is not as easy as they thought. Because they can’t deal with the special environment successfully, such as the change in air pressure, making food taste good is still hard for them.

1.In Paragraph 2, “this problem” means ______.

A. passengers stay long in the plane

B. food on the plane tastes bad

C. passengers have no food to eat 

D. food on the plane is expensive

2.What do airlines do to solve this problem?

A. Get more customers.      B. Offer more food.

C. Improve their food.       D. Reduce the ticket price.

3.As the plane moves up, the change in air pressure reduces        of the sensibility of our taste buds.

A. half                 B. one third

C. one fourth          D. one fifth

4.Why do scientists feel it hard to made food on the plane taste good?

A. The volunteers don’t know about food taste.

B. The volunteers don’t understand them.

C. They can’t find enough volunteers.

D. They can’t deal with the special environment successfully.

5.What is the best title of the passage?

A. Taste of Airplane Food

B. Airplane Travel

C. Scientific Research on Noses

D. The Change in Air Pressure