Please refrain from smoking. ✬

Kindly refrain from smoking. ✬

Please refrain from smoking in this room. ✬

Refrain from smoking here. ✬

Please refrain from smoking cigarettes here. ✬

Please refrain from smoking here. ✬

I refrain from drinking. ✬

I don't know the introduction, but I can sing the refrain. ✬

Please refrain from talking. ✬

I'll refrain from commenting on that. ✬