题目

先化简，再求值：5x2+4﹣3x2﹣5x﹣2x2﹣5+6x，其中x=﹣3． 答案：【考点】整式的加减—化简求值． 【分析】原式合并同类项，得到最简结果，将x的值代入计算，即可求出值． 【解答】解：原式=（5﹣3﹣2）x2+（﹣5+6）x+（4﹣5） =x﹣1， 当x=﹣3时，原式=﹣3﹣1=﹣4． 【点评】此题考查了整式的加减﹣化简求值，涉及的知识有：去括号法则，以及合并同类项法则，熟练     George, when your big brother and your little dog and I walked you up to schools today, you had no idea how I was feeling. You were so excited. You had packed and unpacked your pencils and safety scissors in your backpack a dozen times. I am really going to miss those lazy mornings when we waved your brother and sister off to school. Because you are my youngest, I had learned a few things by the time you came along. I found out that the seemingly endless days of babyhood are gone like lightning. I blinked(眨眼), and your older siblings were setting off for school as eagerly as you did this morning, I was one of the lucky ones; I could choose whether to work or not. By the time it was your turn, the shining prizes of career advancement and a double income had lost their brightness. A splash(溅水) in the pool with you in your bright red boots or "just one more" rereading of your favorite book, Frog and Toad Are Friends, meant more. You didn't go to preschool and I hope that doesn't hold you back. You learned numbers by helping me count the soda cans we returned to the store. I have to admit that in my mind's eye, an image of myself while you're in school has developed, I see myself updating all the photo albums and starting that novel I always wanted to write. As the summer wound down and more frequent quarrels erupted between you and your siblings, I was looking forward to today. And then this morning, I walked you up the steep hill to your classroom. You found the coat hook with your name above it right away, and you gave me one of your characteristically fierce, too-tight hugs. This time you were ready to let go before I was. Maybe someday you will deliver a kindergartner to the first day of school. When you turn at the door to wave good-bye, he or she will be too deep in conversation with a new friend to notice. Even as you smile, you'll feel something warm on your cheek.     And then, you’ll know… 64．What does the author mean by the underlined sentence?        A．She gave up the job with a big salary and prizes.        B．She could only recall her good job at home now.        C．Many good jobs with better pay attracted her but she didn’t take them.        D．Compared with bringing up the baby, work seemed to fade to her. 65．Which statement is NOT TRUE about George’s family according to the letter?        A．George’s parents gave birth to three children        B．The Georges is a double income family.        C．The children had more arguments during the summer.        D．They recyled soda cans. 66．The passage tries to show us          .        A．how excited a child will be on his first day to school        B．how deeply a mother loves her child        C．how many efforts a mother has made to raise a child        D．how a mother plans her future life after her children go to school