to be out of date
1.theory, idea +过时；落伍
You will find that the dictionaries are out of date and mislead you on this point.你会发现这些词典太老旧了, 在这一点上会误导你。
2.technology, equipment +过时；被淘汰；废弃
3.food +
(be bad)过期
The packet of sausages was out of date.这包香肠过期了。
to go out of date
1.idea, technology +过时；落伍
Think how rapidly medical knowledge has gone out of date in recent years.想想最近这些年医学知识更新得有多快。
2.food +
(go bad)过期