てくるCome toward or develop up to now
てくる presents an action or change as moving toward the speaker's reference point. That movement may be physical, or it may be a development extending from the past up to now.
Go, do something, and return
ちょっとコンビニで飲み物を買ってきます。
I'll go buy some drinks at the convenience store and come back.
AnalyzeThe speaker leaves the current place, buys the drinks, and returns to the same reference point.
A common conversational use
コーヒーがないね。
We're out of coffee.
Analyzeじゃ、近くの店で買ってくる。
Then I'll go buy some nearby and come back.
AnalyzeIn casual conversation, the return is often understood from the situation rather than stated separately.
Physical movement toward the observer
子どもが校庭からこちらへ走ってきた。
A child ran over here from the schoolyard.
AnalyzeThe child's movement ends near the speaker or observer.
Development or activity up to now
For a time-based reading, give an earlier starting point or enough history to show a path leading to the present.
朝から気温が少しずつ上がってきた。
The temperature has been rising little by little since this morning.
AnalyzeThe rise began earlier this morning and has continued toward the present moment.
私は大学に入ってから、ずっと環境問題を研究してきました。
I have been researching environmental issues ever since I entered university.
AnalyzeThis presents the research as accumulated activity extending to the present.
Toward now versus onward from now
てくる looks back along a path that reaches the reference point. By contrast, ていく looks away from that point or forward into what will happen next.
More examples
ちょっと郵便局へ行ってきます。
I'm going to the post office and will be back.
Analyze先生が廊下から教室に入ってきました。
The teacher came into the classroom from the hallway.
Analyze遠くから音楽が聞こえてきた。
Music came drifting from far away.
Analyzeここ数年、この町では外国人観光客が増えてきました。
In the past few years, the number of international tourists in this town has been increasing.
Analyze私は子どものころから毎日絵を描いてきた。
I have drawn pictures every day since I was a child.
Analyze雨がだんだん強くなってきた。
The rain has gradually been getting heavier.
Analyze会議が始まる前に、資料をコピーしてきます。
Before the meeting starts, I'll go make copies of the materials and come back.
Analyze