問題詳情

四、閱讀測驗: 請在四個選項中，選出正確的答案。 We depend upon chemistry to live. Chemical reactions are all around us. In nature there are millions and millions of chemical reactions happening all the time. Humans use chemical reactions to make lots of different substances(物質) used in foods, medicines, and materials.   Examples of natural chemical reactions are when an apple starts to turn brown after being bitten, and when green plants use sunlight to make food. Chemical reactions also take place when we make plastics(塑膠) from oil, or when gas burns inside a car to make the engine run.   In a reaction, you start with things called reactants. The new things formed in the reaction are called products. The atoms(原子)in the reactants all end up in the products, so nothing is lost or gained. So why do we get something new? It is because the atoms have arranged themselves into new compounds (複合物). Another thing reactions produce is energy, often in the form of heat. They may need some energy to be put in so that they can take place. So, in a chemical reaction, there is a movement of energy.

46.The passage says that chemical reactions _____  .
(A) are usually difficult to see
(B) are not found in nature
(C) do not take place very often
(D) are very important to us

參考答案

答案：D
難度：簡單0.75
統計：A(1),B(0),C(1),D(6),E(0)

內容推薦

內容推薦