搜题请搜索小程序“爱下问搜题”
问题 选择题

一元二次方程-3x2+3x+4=0，变二次项系数为正，且根不变的是（　　）

A．3x2+3x+4=0

B．3x2-3x+4=0

C．3x2+3x-4=0

D．3x2-3x-4=0

答案

方程的两边同时除以-1，得：

3x2-3x-4=0．

故选D．

单项选择题

患儿，9 个月，呕吐、腹泻3 天，尿量略少，皮肤弹性稍差，口唇微干，眼窝轻度凹陷。血清钠浓度为140mmol/L(92~93 共用题干)

该患儿失水约占其体重的

A．4%

B．8%

C．10%

D．12%

E．14%
查看答案
翻译题

翻译下列句子。

1. You should be quiet when you are in the reading room.

____________________________________________________

2. When I grow up, I'll be a nurse and look after patients.

____________________________________________________

3. If you don't want to go alone, I'll go with you.

____________________________________________________

4. After you use plastic bags, you mustn't throw them about.

____________________________________________________

5. People in the USA can't drink beer or wine before they reach 21.

____________________________________________________
查看答案