When, before, after, while
Clauses that time one action against another: when, before, after and at the same time.
-toki
when, at the time
〜とき
Makes a 'when X' clause after a plain verb, an adjective, or noun + no (kodomo no toki). The verb's tense shows whether X has happened yet.
deru toki denwa suru ne.
I'll call you when I leave.
出るとき電話するね。
deru toki denwa shimasu ne.
I'll call you when I leave.
出るとき電話しますね。
The verb before toki stays plain even in polite speech. Tense sets the order: iku toki katta = bought it on the way there; itta toki katta = bought it there. For 'once X happens, then Y', use -tara: tsuitara denwa suru.
-mae ni
before (doing)
〜前に 〜まえに
Means 'before X' after a dictionary-form verb or noun + no (neru mae ni, shigoto no mae ni). The verb stays non-past even when talking about the past.
deru mae ni denwa suru ne.
I'll call you before I leave.
出る前に電話するね。
deru mae ni denwa shimasu ne.
I'll call you before I leave.
出る前に電話しますね。
Always use the dictionary form: deru mae ni, never deta mae ni.
-te kara
after doing; since
〜てから
Attaches to the -te form to put one action after another (tabete kara deru) or to mark a starting point, 'since' (nihon ni kite kara).
dete kara denwa suru ne.
I'll call you after I leave.
出てから電話するね。
dete kara denwa shimasu ne.
I'll call you after I leave.
出てから電話しますね。
-ta ato de (deta ato de) is the other 'after' and means much the same here.
-nagara
while (doing)
〜ながら
Joins two actions one person does at once, using the masu-stem (arukinagara hanasu). The main action comes last.
eki made arukinagara denwa suru ne.
I'll call you on my walk to the station.
駅まで歩きながら電話するね。
eki made arukinagara denwa shimasu ne.
I'll call you on my walk to the station.
駅まで歩きながら電話しますね。
It only works with one person. 'While you were out' needs -aida or -toki.