that's

剑桥词典

short form of that is or that has
（that is 或 that has 的缩略形式）
That's (= that is) just my opinion . 那不过是我的看法。
That's (= that has) got to be the most ridiculous thing I've ever seen . 那简直是我见过的最荒唐的事情。 返回 that's