go/turn beetroot (red) idiom UK (also go as red as a beetroot); (US go beet red); (go as red as a beet)
（因为尴尬）脸色绯红
to have a red face because you are embarrassed
Whenever I talked about his past life, he would go beetroot. 每当我说起他过去的生活时，他都满脸通红。