Я иду домой один.

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Breakdown of Я иду домой один.

• идти: to go
• домой: home
• один: by myself

Questions & Answers about Я иду домой один.

Why is it иду and not идти?

Идти is the dictionary form, meaning to go / to be going on foot.

In the sentence, you need a conjugated verb, because the speaker is saying I am going.
So идти changes to иду, which is the 1st person singular form:

• я иду — I am going
• ты идёшь — you are going
• он / она идёт — he / she is going

So Я иду домой один literally starts with I am going...

Why is иду used here instead of хожу?

This is a very common question because Russian has two common verbs for go on foot:

• идти / иду — going in one direction, right now, or on one specific trip
• ходить / хожу — going habitually, repeatedly, or in various directions

So:

• Я иду домой = I’m going home / I’m on my way home
• Я хожу домой пешком = I go home on foot / I walk home (in general, habitually)

In your sentence, the speaker is talking about a specific trip home, so иду is the natural choice.

Why is it домой and not or ?