题目

Why Do Autumn Leaves Change Color?We all enjoy the colors of autumn leaves.【1】 To answer this question, we first have to understand what leaves are and what they do.Leaves are nature’s food factories. Plants take water from the earth through their roots and take carbon dioxide from the air.【2】Plants use the sugar as food for energy. The way plants turn water and carbon dioxide into sugar is called photosynthesis（光合作用）. Chlorophyll（叶绿素） helps make photosynthesis happen. Chlorophyll gives plants their green color.As summer ends and autumn comes, the days get short在实验课中，当你得出的实验结论与科学的结论不相符时，应（ ）A．实事求是，坚持自己的结论B．问其他同学，将他们的结果填在自己的实验报告中C．与他人交流后，分析原因，检查自己的实验过程，再重复做几次D．问问老师，以老师的观点为准