I was supposed to wait until after....为什么有两个介词？

参考译文：我应该等到直到....之后。

回答如下：

until after .直到....之后

There was no criticism of her work until after she was downgraded.  

在被降职前她的工作从未受过批评。

The singing and carousing did not end until after midnight.  

人们把酒纵歌，一直闹腾到后半夜。

 It wasn't until after Christmas that I met Paul.  

直到圣诞节之后我才见到保罗。

 I didn'tget back to Brussels until after my demob.  

我在复员之后才回到了布鲁塞尔。

 Fraser did not perform until after inter-mission.  

弗雷泽直到中场休息之后才上场。

 They didn't reach the border until after dark.  

他们天黑以后才到达边境。

 Will the rain keep off until after the game?  

比赛结束后才会下雨 吧 ?

They decided to put the meeting off until after Christmas.  

他们决定把会议推迟到圣诞节以后.

His fame as a poet did not come until after his death.  

他死后才获得诗人的名声.