To preserve food, the growth of bacteria (细菌) must be controlled. Water, warmth, and food are all needed for bacteria to become

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问题     To preserve food, the growth of bacteria (细菌) must be controlled. Water, warmth, and food are all needed for bacteria to become strong and healthy. Some kinds of bacteria need air, but other kinds grow only when air is absent. Extremes of temperature, either hot or cold, can kill bacteria.
  Before electric ice boxes were invented, freezing and cooling were limited by the cold climate. In warmer regions, food was cooled by putting it in the shade, in cold water from the well, or in pits in the ground.
    Cooking will usually kill bacteria if the temperature is high enough and long enough. Certain methods of cooking remove water, and this aids in preserving food. Drying is the oldest and most common method of preserving food. Food can be dried by the sun, by heat or by combination of the two.
    Salt was used by many hunting people. When people began to cat vegetables, salt be came a needed part of their life. Salt helps to preserve food because it slows or stops bacteria growth. Other chemicals besides salt are used in preserving foot. Some people oppose the use of chemicals in food. They say that these chemicals may harm people if the chemicals can harm bacteria.
The method of salting the food      .

选项 A、was not used in the past
B、involves tile use of chemicals
C、is not liked by most people
D、is no longer used by hunter

答案B

解析 根据题干中的关键词salting the food定位到文章末段第三、四句Salt helps to preserve food because it slows or stops bacteria growth. Other chemicals besides salt are used in preserving food.可知,盐能帮我们保存食物,因为盐能减缓或终止细菌的生长。除了盐以外的一些化学物质也被用于食物的保存。由Other chemicals besides salt可以得知盐也属于化学物质,答案为B。当然我们也可以用常识判断。
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