题目

    Australians have been warned they face a life or death decision over their water—drink recycled sewage(污水)or die．    With the drought(干旱)continuing，the country is set to be forced to use purified(净化的)waste water for drinking．even though there is great opposition to the measure．     Queensland has become the first state to introduce tile policy after a warning from its premier． “I think in the end，because of the drought，all of Australia is going to end up drinking recycled purified water．”said Peter Beattie．     “These are difficult decisio圆柱半径扩大到原来的3倍，高缩为原来的13，它的体积（　　）A．不变B．扩大到原来的3倍C．缩小为原来的13