题目

下图甲是“观察植物细胞”实验中所使用的普通光学显微镜结构示意图，目镜的放大倍数是10×，两个物镜的放大倍数分别是10×和 40×，根据图回答问题。 （1） 生态系统中除外，生物都是由构成。 （2） 使用显微镜时，光线较暗时，要使用遮光器上的光圈和反光镜上的面镜。 （3） 对光成功后，这位同学在显微镜下观察到如乙图所示的洋葱片叶表皮装片的情况。视野 中出现的中间亮且四周暗的圆圈很可能是。若将视野中的物像移到(Jack=J Susan=S)S: It’s Sara’s birthday the day after tomorrow. 1._________________________?J: Does she like reading? 2. _____________________.S: Well ,she has had lots of books already. Besides, her birthday present last year was also a book.J: 3. ______________________________?S: No, she doesn’t like basketball, but she likes football.J: Get her a football, then?S: 4._______________________________?J: I have no idea, about 20 dollars, maybe.S: I have only 6 dollars. 5.________________________?J: I have eight. Why not go and ask John if he would like to join us?S: That’s really a good idea. Let’s do that right away.A.We can buy her a bookB.Do you know how much a football costsCHow much do you haveD.What shall we buy for her birthdayE. What do you think of her books?F. How about a basketballG.Don’t be afraid.