～ながら

音楽を聴きながら宿題をしました。
ongaku o kikinagara shukudai o shimashita
music-(direct object marker)-listen while-homework-did
While listening to music, (I) did homework.

聞く　－＞　 聞き ます　－＞　聞きながら
する　－＞　 し ます　－＞　しながら

Note that the first verb (the one with ながら has no tense (not past or present).

A useful set phrase using ながら is 残念ながら zannen nagara - That's too bad, but...:
残念ながら、ピーマンを全部食べなさい。
zannen nagara, pi-man o zenbu tabenasai.
That's too bad-green pepper-(direct object)-all-eat(command).
It's a cryin' shame, but eat all your veggies!