题目

What is the purpose of reading or studying? If you can’t remember what you read or study, it will be a waste of time.  36  One useful aid that does help you remember what you study is to have a specific purpose or reason for reading. Why does a clerk in a store go away when your reply to her offer to help is, No, thank you, I'm just looking.? Both you and she know that if you aren't sure what you want, you are not likely to find it. But suppose you say instead, Yes, thank you. I want a pair of sun glasses. She says, Right this way, please.” It’s quite the same with your studyin如果盖盖玻片的方法不恰当，很容易出现气泡，影响观察效果。下列四种盖盖玻片的方   法中，最不容易出现气泡的是（图中半扁圆形结构代表水滴，箭头代表盖盖玻片的方向）