搜题请搜索小程序“爱下问搜题”
问题 选择题
下列是一元一次方程的有（　　）
①S=ab，②2+5=7，③
x
2
-1=3，④x=0．
A．1个B．2个C．3个D．4个
答案

①S=ab是三元二次方程．故①错误；

②2+5=7中不含有未知数，所以它不是方程，故②错误；

③由

x
2
-1=3得到：x-8=0，符合一元一次方程的定义，故③正确；

④x=0符合一元一次方程的定义，故④正确；

综上所述，符合条件是：③④，共2个．

故选：B．

阅读理解

One day a young girl was driving with her father and it started to rain. “What should I do?” the girl asked. “Keep driving,” her father said. Cars began to pull over (靠 …. 停车) to the side of the road. “What should I do?” the young girl asked. “小题1:____” her father said. “But don’t stop.”

A few feet up the road, she noticed that even more drivers were also pulling over. “小题2:_____Everyone else is pulling over!” she told her father. “Don’t give up, just keep driving!” her father told her.

The rain continued, but she never stopped driving and soon she could see a little more clearly. After a few miles she was again on dry land and the sun came out.

“小题3:____” her father said.

“But why now?” the girl asked.

“When you get out, look back at all the people that gave up and are still in the rain.

小题4:  ” said her father.
查看答案
判断题

葡萄酒能帮助减肥。
查看答案