É importante revisar a gramática antes da prova.

É importante means It is important.

Portuguese often uses this impersonal structure:

• É + adjective + infinitive
• É importante estudar.
• É bom descansar.
• É difícil entender.

So in É importante revisar a gramática, the idea is It is important to review grammar.

Unlike English, Portuguese does not need a separate word like it here. The é already works as the verb is in this kind of structure.

After expressions like é importante, Portuguese commonly uses the infinitive verb.

So:

• É importante revisar... = It is important to review...
• É necessário estudar... = It is necessary to study...

The verb revisar is not conjugated because it is functioning like to review in English.

If you conjugated it, the structure would change and you would need a subject, for example:

• É importante que você revise a gramática.
  = It is important that you review the grammar.

That version is also correct, but it is a different structure.

The accent is important because é and e are different words:

• é = is
• e = and

So:

• É importante = It is important
• gramática e vocabulário = grammar and vocabulary

The accent also shows the stressed vowel sound.

Portuguese uses definite articles more often than English.

So a gramática literally means the grammar, but in English we might simply say grammar.

In Portuguese, using the article here sounds natural because it refers to the subject or area of study in a general sense.

Compare:

• revisar a gramática = review grammar / review the grammar
• estudar o português = study Portuguese
• aprender a matemática = learn math

English often drops the article where Portuguese keeps it.

Literally, antes da prova means before the test.

Breakdown:

• antes = before
• da = de + a
• prova = test / exam

So antes da prova is literally before of the test, but natural English is before the test.

Portuguese often uses antes de before a noun:

• antes da aula = before class
• antes do almoço = before lunch
• antes da viagem = before the trip

Because de + a contracts to da in Portuguese.

This kind of contraction is very common:

• de + o = do
• de + a = da
• de + os = dos
• de + as = das

So:

• antes da prova
• not antes de a prova

These contractions are normally required in standard Portuguese.

Yes. Portuguese allows some flexibility.

The original sentence:

• É importante revisar a gramática antes da prova.

A very natural variation is:

• Antes da prova, é importante revisar a gramática.

Both are correct. The difference is mainly emphasis:

• starting with É importante emphasizes the importance
• starting with Antes da prova emphasizes the time

In Brazilian Portuguese, prova usually means a test or exam, especially in school or university contexts.

Examples:

• Tenho prova amanhã. = I have a test tomorrow.
• A prova foi difícil. = The test was difficult.

Depending on context, English could translate it as:

• test
• exam
• sometimes quiz, though that is less exact

Yes, revisar is very natural here.

In a school context, revisar a gramática means to go over grammar again before a test.

Related verbs:

• estudar = to study
• revisar = to review
• rever = to see again / review again, but less common in this study-context phrase

So:

• É importante estudar antes da prova. = It is important to study before the test.
• É importante revisar a gramática antes da prova. = It is important to review grammar before the test.

Both are correct, but revisar specifically suggests going over material you have already learned.

A simple approximate pronunciation is:

EH im-por-TAHN-chee hey-vee-ZAHR a gra-MAH-chee-kah AHN-ches dah PROH-vah

A few helpful notes:

• É sounds like eh
• importante in Brazil often sounds like imporTANchi
• revisar has a z sound in the middle
• gramática has stress on má
• antes often sounds like ANCH-es or AHN-chis, depending on accent
• prova has an open o for many speakers

Pronunciation varies by region, but this will help you say it in a natural Brazilian way.

It is possible to hear article omission in some cases, but a gramática is the more standard and natural choice here.

For a learner, it is best to say:

• É importante revisar a gramática antes da prova.

Leaving out the article may sound less natural or less complete in this sentence.

As a general rule, Portuguese uses articles more often than English, so when in doubt, keep the article.