简述保险的特征
参考答案：
危险依赖性，危险选择性，行为盈利性，分担社会性，资金公益性，目地合法性，利益对等性，金融中介性
Measures have been taken to solve the problem，but it may be some time________the situation
improves.[ ]
A. since
B. when
C. unless
D. before
什么是水资源？我国水资源有何特点？
