Learn Hardcore Ukrainian: Мені треба чистити зуби зубною щіткою з зубною пастою щоранку та щовечора. - I need to brush my teeth with a toothbrush and toothpaste every morning and evening.

мені is the dative case form of я (“I”). With the impersonal modal треба, the person who needs something appears in the dative. So мені треба literally means “to me it is necessary,” i.e. “I need to….”

Why is треба used here, and what does it mean?

треба is an impersonal modal word expressing necessity or obligation (“need to,” “have to”). It never changes for person or number; the experiencer goes in the dative (мені), and the action follows in the infinitive.

Why is чистити in the infinitive form?

After modals like треба you always use the infinitive for the main verb. Thus “have to brush” is треба чистити, not a conjugated form like треблю.

Why is зуби in the plural accusative?

зуби is the direct object of чистити, so it takes the accusative case. Since you normally brush both upper and lower sets, you use the plural form зуби.

Why are зубною щіткою and з зубною пастою in the instrumental case?

The instrumental case shows the tool or means of an action in Ukrainian. You brush your teeth with (i.e. by means of) a toothbrush and toothpaste. Grammatically:
• зубна щітка → зубною щіткою (instrumental singular)
• зубна паста → зубною пастою (instrumental singular), here with the preposition з (“with”)
They answer the question “чим?” (“with what?”).

What is the difference between щоранку/щовечора and кожного ранку/кожного вечора?

Щоранку and щовечора are adverbs of frequency formed by prefixing що- (“each, every”) to ранок/ вечір, meaning “every morning,” “every evening.” You can also say кожного ранку and кожного вечора, which are adjective-noun phrases “of every morning/evening.” Both are correct; щоранку/ щовечора is simply shorter and very common in speech.

Why is the conjunction та used instead of і between щоранку та щовечора?

Both та and і mean “and.” і is the most neutral conjunction, while та can sound slightly more formal or emphatic. You could also say щоранку і щовечора without any change in meaning.

Can Мені треба be replaced by Мені потрібно, and is Треба мені also possible?

Yes. потрібно is a more formal synonym of треба; Мені потрібно чистити зуби… is equally correct. As for Треба мені, it’s grammatically fine but rather emphatic and less neutral in everyday speech.

Is the word order in this sentence fixed?

Ukrainian allows flexible word order for emphasis. The most neutral pattern is Мені треба чистити зуби…, but you could shift elements (e.g. Чистити зуби мені треба…) to highlight a particular part. The cases (dative, accusative, instrumental), not word order, signal each word’s role.