電話が鳴ったとき、ちょうど外出していた。

When the telephone rang, I was just going out.

電話(でんわ)が鳴(な)ったとき、ちょうど外出(がいしゅつ)していた。

Denwa ga natta toki, chōdo gaishutsushiteita.

電話 (でんわ)

telephone call; phone call; telephone (device); phone

が (が)

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

鳴る (なる)

to sound; to ring; to resound; to echo; to roar; to rumble

とき (とき)

regular (stops at every station) Jouetsu-line Shinkansen

丁度 (ちょうど)

just; right; exactly

外出 (がいしゅつ、そとで)

outing; trip; going out

Reading: デン

Meaning: electricity

Readings: ワ、はな.す、はなし

Meanings: tale, talk

Readings: メイ、な.く、な.る、な.らす

Meanings: chirp, cry, bark, sound, ring, echo, honk

Readings: ガイ、ゲ、そと、ほか、はず.す、はず.れる、と-

Meaning: outside

Readings: シュツ、スイ、で.る、 -で、だ.す、 -だ.す、い.でる、い.だす

Meanings: exit, leave, go out, come out, put out, protrude