问题 单项选择题

设备从投入使用开始,直到因物质磨损严重而不能继续使用、报废为止所经历的全部咿间,这是指设备的()。

A.物质寿命

B.技术寿命

C.经济寿命

D.有效寿命

答案

参考答案:A

阅读理解

阅读理解。

       Why do you think people who live in some hot countries eat very spicy (辛辣的) food? Is it because the

spices make the food taste better? Is it just because their parents and grandparents and great-grandparents liked

hot food, or is there some connection between spices and healthy food?

       Researchers from Cornell University think that it is because spice plants have some important chemicals

(化学物质). These chemicals can kill bacteria (细菌) which spoil food. "Most common spices can kill 75 to 100

percent of the bacteria in food," explains one of the scientists. The bacteria grow more easily and spoil food

more quickly at higher temperatures. For this reason, it is more difficult to keep food from spoiling in hot

climates.

       Do you like your food spicy? Your answer probably tells something about the country you come from. If

you like spicy food, it is possible that hundreds of years ago, when there were no fridges, people in your

country started using spices to keep the food from spoiling. The traditional spicy dishes helped those people to

live longer, healthier lives. Today, in a time of fridges, the spices just make the food taste good.

1. The chemicals in spices keep food from spoiling by_______.[ ]

A. making food taste better

B. making food hotter

C. killing bacteria in food

D. preventing bacteria getting into food

2. Food goes bad more quickly in hot climates because _______. [ ]

A. high temperature makes more bacteria

B. high temperature helps bacteria grow faster

C. bacteria get used to hot food

D. bacteria spoil food only at high temperature

3. According to the passage, spices are useful in an the following things except _______.[ ]

A. replacing fridges

B. helping you to live longer

C. helping to keep you healthier

D. making your food taste better

问答题