Tehnički pregled je sutra.

Because pregled is a masculine singular noun, and adjectives in Serbian must agree with the noun in gender, number, and case.

So:

• tehnički pregled = masculine singular
• tehnička kontrola = feminine singular
• tehničko... = neuter singular

Here, tehnički matches pregled.

It is in the nominative singular.

In this sentence, tehnički pregled is the subject of the sentence, and subjects are normally in the nominative case.

So the structure is basically:

• Tehnički pregled = the subject
• je = is
• sutra = tomorrow

Je is the 3rd person singular present tense of the verb biti = to be.

So it means is.

In this sentence:

• Tehnički pregled je sutra.
• literally: The technical inspection is tomorrow.

It links the subject to the time expression sutra.

Usually, no in normal standard Serbian.

You normally say:

• Tehnički pregled je sutra.

Leaving out je would sound incomplete in ordinary speech, although you might see that kind of omission in very informal notes, headlines, reminders, or text-message style language.

So for a learner, the safe choice is:

• use je

Because sutra is an adverb, not a noun phrase.

Serbian says simply:

• danas = today
• sutra = tomorrow
• prekosutra = the day after tomorrow
• juče = yesterday

So you do not need a preposition like on or in as you would in some English expressions.

Correct:

• Tehnički pregled je sutra.

Not:

• Tehnički pregled je u sutra.

Yes, you could also say Sutra je tehnički pregled.

Serbian word order is more flexible than English. The basic meaning stays the same, but the emphasis changes slightly.

• Tehnički pregled je sutra.
  Focuses first on the technical inspection.

• Sutra je tehnički pregled.
  Focuses first on tomorrow.

The first version sounds very natural as a neutral statement.

Yes. In everyday Serbian, tehnički pregled very often refers to a vehicle inspection / roadworthiness inspection, especially for a car.

Even though the words literally mean something like technical inspection, in real life many speakers will immediately think of the official car inspection.

So context matters, but this phrase commonly has that specific practical meaning.

A simple English-friendly guide would be:

• Tehnički ≈ tekh-NEECH-kee
• pregled ≈ PREH-gled
• je ≈ yeh
• sutra ≈ SOO-tra

A few useful notes:

• č sounds like ch in church
• j sounds like English y in yes
• h is pronounced, unlike in many English words
• r in Serbian is usually trilled or tapped more than in English

Because Serbian does not have articles like English a/an/the.

So tehnički pregled can mean:

• a technical inspection
• the technical inspection

Which one is meant depends on context.

In this sentence, English will usually translate it with the if both speaker and listener already know which inspection is being discussed.

Pregled is a broader word than just inspection.

Depending on context, it can mean:

• inspection
• check-up
• examination
• review / overview

For example:

• lekarski pregled = medical examination
• pregled automobila = inspection of the car
• pregled događaja = overview of events

So pregled is a general noun, and the adjective or context tells you what kind of examination or inspection it is.