问题描述:
three pipes a,b and c can fill a tank in 6 hours .after working at it together for 2 hours .c is cl
谁能帮我翻译一下这句什么意识
谁能帮我翻译一下这句什么意识
问题解答:
我来补答展开全文阅读
问题描述:
问题解答:
我来补答