题目

衡量环境承载力的重要指标是（ ）  A．资源的数量                 B．人口数量                  C．人口出生率                 D．人口自然增长率   答案：B—It’s too late. I have to go now.—Oh, it’s raining outside. Don’t leave ______ it stops.A. since B. until C. while D. when