there's no doubt that 和it's no doubt that区别

there's no doubt that 和it's no doubt that区别
我刚才查了好多地方意思都说意思差不多或者有说没有it's no doubt that 的说法.但是很多选择题里面同时出现这两个的时候都是选的there's no doubt that到底是怎么样么?