semper ubi sub ubi
Always wear underwear. (Literally, ‘always where under where’).
And on the subject of “below” or “under,” there is the famous line that every student of Latin knows by heart: Semper ubi sub ubi.
ADJ.
ready
The team had several sub ready players on the bench waiting for their chance to play.
VERB + SUB
ate, keep, want
I ate a sub for lunch because I didn't have time to cook dinner.
SUB + NOUN
investigation, quid, rome, rosa, sandwiches
The detective opened a sub investigation into the company's financial records.
PREP.
in
I had to sub in for my colleague who called in sick yesterday afternoon.