题目

John, look at the time. ____ you play the piano at such a late hour? A. Must       B. Can                  C. May      D. Need   答案：A8．先化简，再求值．（1-$\frac{3}{x+1}$）$÷\frac{{x}^{2}-4}{x+1}$，其中x是方程x2-5x+6=0的根．