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 plane.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（氣壓）reduces one third of the sensibility（感覺）of our taste buds.So our taste buds（味蕾） 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

food on the plane tastes bad

food on the plane tastes bad

.
（2）從文中找出"If they don't do that，the food could taste nothing．"的同義句。

Without doing so，the food would be tasteless.

Without doing so，the food would be tasteless.

（3）根據(jù)閱讀內(nèi)容完成下列短文，每空不超過2個單詞。
    Nowadays many scientists are trying their best

to make

to make

the food on the plane taste better，but it is

more difficult

more difficult

than they thought.Scientists ask the volunteers to lie that way

so

so

they can write down what they

feel

feel

about the food taste.