题目： 方程x2-2=0的两个根为（ ）A．x1=x2=2B．x1=2，x2=-2C．x1=x2=2D．x1=2，x2=-2 答案： 方程x2-2=0，移项得：x2=2，开方得：x=±2，∴x1=2，x2=-2．故选D
题型：选择题 The room was very dark, so I couldn't see anything _____. [ ]A. enough clearly B. enough clear C. clearly enough D. clear enough 查看答案
