Je ne connais pas l'heure exacte.

Connais is the 1st person singular present tense form of connaître.

So:

• je connais = I know
• tu connais = you know
• il/elle connaît = he/she knows

In this sentence, Je connais means I know in the present tense.

In standard French, a basic negative is usually made with ne ... pas around the conjugated verb.

Here:

• Je = subject
• ne = first part of the negative
• connais = conjugated verb
• pas = second part of the negative

So:

• Je connais = I know
• Je ne connais pas = I do not know

This is one of the most important word-order patterns in French.

This is a very common learner question.

A useful basic rule is:

• connaître
  • noun
• savoir
  • clause or infinitive

In this sentence, l'heure exacte is a noun phrase, so connaître works naturally:

• Je ne connais pas l'heure exacte.

A very common alternative with savoir would be:

• Je ne sais pas quelle heure il est exactement.

In real everyday French, you may also hear things like Tu sais l'heure ?, so native usage is a bit more flexible than the simple classroom rule. But the sentence you were given is completely correct.

Because heure begins with a mute h. In French, le and la usually shorten before a vowel sound or a mute h:

• le ami → l'ami
• la heure → l'heure

This shortening is called elision.

So even though heure is feminine, you still write l'heure, not la heure.

The h in heure is silent. French calls this an h muet.

That means:

• you do not pronounce an English-style h
• the article contracts: l'heure
• the word behaves as if it begins with a vowel sound

So heure is pronounced roughly like eur at the beginning, not like h-eur.

In French, most adjectives come after the noun they describe.

So:

• l'heure exacte = the exact time

That word order is normal. While some very common adjectives often come before the noun, exact is generally placed after it.

So l'exacte heure would sound unusual here.

Because heure is a feminine noun.

French adjectives usually agree with the noun they describe in:

• gender: masculine or feminine
• number: singular or plural

So:

• masculine singular: exact
• feminine singular: exacte

Since heure is feminine singular, the adjective must also be feminine singular:

• l'heure exacte

A careful standard pronunciation is approximately:

/ʒə nə kɔ.nɛ pa lœʁ ɛɡ.zakt/

A few helpful notes:

• Je sounds like zhuh
• connais sounds roughly like ko-nay
• heure has no pronounced h
• exacte ends with a pronounced kt sound

In everyday speech, the sentence is often pronounced more smoothly and quickly than a dictionary-style version.

Yes. In spoken informal French, many speakers drop ne.

So you may hear:

• Je connais pas l'heure exacte.

That is very common in conversation.

But in standard writing and more careful speech, you should keep ne:

• Je ne connais pas l'heure exacte.

So the full version is the safest one for learners.

Yes. A very natural alternative is:

• Je ne sais pas quelle heure il est exactement.

This is especially common because French often uses savoir with a full clause such as quelle heure il est.

So both of these are correct and natural:

• Je ne connais pas l'heure exacte.
• Je ne sais pas quelle heure il est exactement.

The sentence you were given is shorter and more direct.