N4
ていく
To ~ and go, To go on, To start
今日はうちで食べていく?
Do you want to eat at my place before you go today?
Explanation
「ていく」 has 4 uses
1Moving away
Movement away from the speaker: 「鳥が飛んでいった」 the bird flew away, 「持っていく」 take something along.
大きい音で、鳥が飛んでいく。
At the loud noise, the birds fly away.
今晩は雨が降ると聞いたから、傘を持って行った。
Because I heard that it was going to rain tonight, I took an umbrella.
2Do something, then go
Do one thing first and then leave: 「朝ご飯を食べていきます」 I'll have breakfast before I go.
今日はうちで食べていく?
Do you want to eat at my place before you go today?
友達にプレゼントを買っていく。
I am going to buy a present and take it to my friend.
3From now on
Something continues or keeps changing from now into the future: 「続けていく」 keep going, 「上手になっていく」 keep getting better.
毎日ゴルフの練習をしたらだんだんと上手くなっていく。
When you practice golf everyday, you will gradually get better.
今から日本語の勉強をし始めたら、だんだん上手になっていくよ。
If you start studying Japanese now, you will go on to become more proficient.
4Fading away
Something slowly shrinks or fades until it is gone: 「消えていく」 fade away, 「小さくなっていった」 grew smaller and smaller.
船がだんだん小さくなっていった。
The ship grew smaller and smaller as it sailed away.
朝になって、空の星が一つずつ消えていった。
As morning came, the stars disappeared one by one.