题目

下列各式从左边到右边的变形是因式分解的是 （ ）A．(a＋1)(a－1)＝a2－1B．a2－6a＋9＝(a－3)2C．x2＋2x＋1＝x(x＋2x)＋1D．－18x4y3＝－6x2y2·3x2y 答案：【答案】B【解析】分解因式就是把一个多项式化为几个整式的积的形式．因此，要确定从左到右的变形中是否为分解因式，只需根据定义来确定．解：A、是多项式乘法，不是因式分解，错误；B、是因式分解，正确．C、右边不是积的形式，错误；D、左边是单项式，不是因式分解，错误．故选B．本题的语法选择（共10小题，每小题1.5分，满分10分）阅读下面短文，按照句子结构的语法性和上下文连贯的要求，从1—10各题所给的A、B、C和D项中选出最佳选项。It is often said that eyes can speak. Do you have such kind of__ _? In a bus you may look at a stranger, but not too __ _ If he notices that he is being looked at, he may __ _ uncomfortable. It is the same in daily life. When you are looked at for several more times, you will look __ _ up and down in order to __ _ if there is anything wrong with you. If __ _ goes wrong, you will feel angry with person who is looking at you. __ _ can speak, right?Looking too long at someone may seem to be impolite. But sometimes things are__ _ . If you wish to draw someone’s__ _ , you may look at him or her for more than ten seconds. For lovers, they enjoy looking at each other longer to show the love that words cannot __ _ .Clearly, eyes communication should be done according to the relationship between the two people and the certain situation.1.A.future B. fear C. experience D. exercise2.A.late B. long C. low D. loud3.A.feel B. smell C. sound D. taste4.A. itself B. himself C. myself D. yourself5.A. see B. guess C. hear D. expect6.A. something B. nothing C. everything D. anything7.A. Ears B. Eyes C. Mouth D. Noses8.A. different B. difficult C. Tiring D. boring9.A. direction B. lesson C. attention D. trouble10.A. Write B. Print C. read D. Express