Коли на вулиці слизько, я йду обережно.

In Ukrainian, you often do not use a present-tense verb meaning is/are in sentences like this.

So:

• На вулиці слизько = It is slippery outside / on the street
• literally, something like Outside slippery

This is completely normal in Ukrainian. The idea of is is understood automatically.

Коли means when here.

So the first part:

• Коли на вулиці слизько = When it’s slippery outside

Be careful: коли can also mean when? as a question word:

• Коли ти прийдеш? = When will you come?

In your sentence, it introduces a subordinate clause, so it means when in the sense of whenever / when it happens that.

На вулиці literally means on the street or in the street, but in everyday Ukrainian it very often means outside / outdoors, especially when talking about weather or conditions outdoors.

Examples:

• На вулиці холодно. = It’s cold outside.
• На вулиці темно. = It’s dark outside.

So in your sentence, на вулиці слизько is a very natural way to say it’s slippery outside.

Слизько is an adverb-like predicative word used to describe a condition or state. In English, we often translate it with an adjective phrase like it’s slippery.

Compare:

• слизький = slippery (regular adjective, masculine form)
• слизько = slippery in the sense of it is slippery

Examples:

• Стіл слизький. = The table is slippery.
• Тут слизько. = It’s slippery here.

So in your sentence, слизько is not describing a noun directly; it describes the general condition outside.

This is an important Ukrainian verb distinction.

• йти / іти = to go, to be going in one direction, at a specific time
• ходити = to go / walk regularly, habitually, or in different directions

So:

• я йду обережно = I am walking carefully / I go carefully
• я ходжу обережно would sound more like I walk carefully in general / as a habit

In this sentence, the speaker is talking about what they do in that situation, so йду sounds natural.

The comma separates the subordinate clause from the main clause.

Structure:

• Коли на вулиці слизько, = subordinate clause
• я йду обережно. = main clause

This is just like English:

• When it’s slippery outside, I walk carefully.

So the comma is required here.

Yes. Ukrainian word order is flexible.

Your sentence:

• Коли на вулиці слизько, я йду обережно.

A possible alternative:

• Я йду обережно, коли на вулиці слизько.

Both are correct. The difference is mainly emphasis:

• starting with Коли на вулиці слизько emphasizes the condition first
• starting with Я йду обережно emphasizes the action first

The original version sounds very natural.

Обережно means carefully or cautiously.

It comes from обережний = careful / cautious.

So:

• я йду обережно = I walk carefully

This is an adverb, so it describes how the person walks.

Compare:

• обережний чоловік = a careful man
• йти обережно = to walk carefully

It could be omitted, because the verb йду already shows the subject is I.

So both are possible:

• Коли на вулиці слизько, я йду обережно.
• Коли на вулиці слизько, йду обережно.

Including я makes the subject more explicit and can add a little emphasis or clarity. Ukrainian often drops subject pronouns when they are clear from the verb form.

Both йду and іду are used. They are variants of the same verb form, meaning I go / I am going.

So you may hear:

• я йду
• я іду

In modern standard Ukrainian, йду is very common and natural, especially after a vowel or at the start of a phrase. Learners will most often encounter йти and forms like йду.

It can express a general repeated behavior in that situation:

• When it’s slippery outside, I walk carefully.

Even though йду is a present-tense form that often refers to a specific action, in sentences with коли it can also describe what someone does whenever that situation occurs.

So the sentence is natural as a general statement of behavior.

A more literal breakdown would be:

• Коли = when
• на вулиці = outside / on the street
• слизько = it is slippery
• я йду = I go / I am walking
• обережно = carefully

So, very literally:

When outside is slippery, I go carefully.

That literal version is not natural English, but it helps show how the Ukrainian sentence is built.