题目

下列方程中，是关于x的一元二次方程的是（ ）A. x2+3y＝1 B. x2+3x＝1 C. ax2+bx+c＝0 D. 答案：【答案】B【解析】根据一元二次方程的定义解答：未知数的最高次数是2；二次项系数不为0；是整式方程；含有一个未知数．由这四个条件对四个选项进行验证，满足这四个条件者为正确答案．A、x2+3y＝1，含有两个未知数，故不是一元二次方程；B、x2+3x＝1，是一元二次方程，故此选项正确；C、ax2+bx+cThere are four people in my family. My father is a police officer. His work is kind of dangerous. He's very busy. He often has meals outside. Sometimes we can't see him all day. But I love him very much. My mother is a bank clerk, but she wants to be a reporter. She says her job is boring and being a reporter is interesting,because she can meet many interesting people. My brother is a waiter. He likes his work, because he thinks he can meet many new friends when he works. I'm a middle school student. I study hard because I want to be a teacher. I think it's not difficult for me.根据短文内容,判断下列句子正(T)误(F)【1】My father works in another（另一个）city, so we can't see him all day sometimes.【2】My mother likes to be a bank clerk.【3】My mother wants to be a reporter, because she wants to meet many interesting people.【4】My brother works in a restaurant. He likes to make new friends.【5】I want to be a teacher. I think it's difficult for me.