１時間以内に戻ってきます。

１時間以内に戻ってきます。

I'll be back within an hour.

１時間(じかん)以内(いない)に戻(もど)ってきます。

Ichi jikan inaini modottekimasu.

一 (いち)

one; best; first; foremost; beginning; start; bottom string (on a shamisen, etc.)

時間 (じかん)

time; hours

戻る (もどる)

to turn back (e.g. half-way); to return; to go back; to recover (e.g. something lost); to be returned; to rebound; to spring back

Readings: ジ、とき、 -どき

Meanings: time, hour

Readings: カン、ケン、あいだ、ま、あい

Meanings: interval, space

Readings: イ、もっ.て

Meanings: by means of, because, in view of, compared with

Readings: ナイ、ダイ、うち

Meanings: inside, within, between, among, house, home

Readings: レイ、もど.す、もど.る

Meanings: re-, return, revert, resume, restore, go backwards