后四十

back foot───后脚

back forties───四十年代后

back floats───后浮动

back copy───备份

back feet───后脚

back float───反向浮动

back foci───后焦点

back focus───[摄]后焦点；反焦点；象方焦点

back four───四卫式

Cheng and Gao edition's back forty chapters as well as its artistic value are the pending problems in "Red" study.───程高本后四十回之真伪与艺术上之得失，是红学研究的一大积案。

Forty minutes later, they were back at his place.───40分钟后，他们回到他的地方。

Bly: Donald Hall and I have been sending poems back and forth twice a week for forty years.───布莱：四十多年来，唐纳德·哈尔和我每星期都互相传送诗歌两次。

TV history, as I've said, goes back forty years.───电视的历史，正如我已经说过了，回到四十年。