阅读《人类的“老师”》课文文段,回答问题
“此外,人们模仿袋鼠造出了会跳跃的越野汽车,模仿某些贝壳制成了外壳坚固的坦克……自然界的生物真是人类的好“老师”啊!”这句话在文中起到了什么作用?
A. Today is Sunday.
B. He flies a kite.
C. The girl plays with her teddy bear.
D. We read books.
E. They play catch with a ball.
—Why didn't you cry for help when you were robbed (被抢劫)?
—If I opened my mouth, they might find my four gold teeth. That would be !
下列各项古代工、农业活动中,其原理不涉及化学反应的是( )
A.水车灌溉
B.粮食酿醋
C.黏土烧砖
D.湿法炼铜