通常称为社会效益的是( )。
A．正面影响
B．负面影响
C．适应性
D．不适应性
参考答案：A
设x1、x2为方程2x2-mx+m=0的两个实数根，且x12+x22=3，求m的值．
根据答句写问句。
1. ________________________?
It's June lst today.
2. ________________________?
It's Tuesday tomorrow.
3. _________________________?
No, we can't swim in winter. The water is too cold.
4. __________________________?
Yes, I go swimming with my friends on weekend.
5. _____________________________?
My birthday is in October.
