下列适合于薪炭林树种选择的要求（）。
A.早实高产性
B.速生丰产优质性
C.生长迅速萌芽力强
D.根系发达落叶丰富
参考答案：C
It's Sunday tomorrow. We go to school.[ ]
A. don't have to
B. haven't to
C. not have to
D. had not better
衡量水资源丰歉的指标？
