draw a veil over something idiom UK
不提及，避讳（某个话题）
If you draw a veil over a particular subject, you do not speak about it because it is unpleasant and you do not want to think about it.
Yes, well I think we'll just draw a veil over what went on last night. 是啊，我想昨晚发生的事情我们就不要提了。