A specific regular expression for Trados Studio display filter needed

Forum: SDL Trados support
Topic: A specific regular expression for Trados Studio display filter needed
Poster: Alex Marshall

This is probably a no-brainer for people like Jerzy Czopik, but I have to ask this question anyway:

I need the regular expression for the Trados Studio display filter that will filter out all English-only source segments in my Russian-English file. The file contains multiple source segments that are already in English (and do not need translating as such). I'd like to copy them all to target and confirm just to get them out of the way.

I know there is a regular expression for this (I did this once before), but now it eludes me.

Thanks!