若x=n是方程x2+mx+n=0的根,且n≠0,则m+n等于()
A:-12
B:12
C:1
D:-1
下列温度最接近23℃的是( )
- Doctor, how are the twins going? - Don't worry. _______of them needs_______.
空气不能在水中溶解。( )
中=____国=____奥=____运=____