" To be supposed to do something" is to be expected to do something.

“To be supposed to do something”是被期望做某事。

To do something prematurely means to do it before you should do it, before you are supposed to do something.

过早地做某事意味着在你应该做之前，在你应该做某事之前就做了。

So, somebody was supposed to do something, but it didn't happen and everybody got confused, nobody knows what happened - it's a snafu.

所以，有人应该做点什么，但没有发生， 每个人都感到困惑， 没有人知道发生了什么——这是一场混乱。

" To be responsible" means to be the person whose job it is to do something, the person who has an obligation to do something, who is supposed to do something.

“负责” 意味着做一个有责任做某事的人， 一个有责任做某事的人， 一个应该做某事的人。