III 閱讀測驗       Understanding the science of food can help you cook a meal. For instance, if you haveever stood nearby while an onion is being cut, you know it can make you cry. Peeling orcutting the onion allows chemicals inside it to mix and form acid. However, this can beprevented simply by keeping the onion in the refrigerator, or by cutting it under water.       You have also noticed that if you cut certain kinds of fruit, such as apples and bananas, theyturn brown if not eaten right away. This happens because the fruit contains a chemical thatreacts with oxygen. One way to prevent this is with juice from a lemon or tangerine. That iswhy fruit salad has orange juice in it. The acid in the juice prevents the chemical reaction.Whether you are preparing a snack or learning how to cook, science is a part of everythingyou do. In fact, you might say that to be a cook, you must also be a scientist!
【題組】39. What causes people to cry when an onion is being cut?
(A) One chemical inside produces acid.
(B) Chemicals inside mix and produce acid.
(C) Some chemical inside reacts with oxygen and produces acid.
(D)The acid inside mixes with chemicals, which makes people cry.