Precisamos proteger a natureza.

Precisamos is the 1st person plural form of the verb precisar in the present tense.

• eu preciso = I need
• você/ele/ela precisa = you/he/she needs
• nós precisamos = we need
• eles/elas precisam = they need

So in this sentence, precisamos means we need.

In Portuguese, the subject pronoun is often omitted when the verb form already makes the subject clear.

Because precisamos clearly shows we, Brazilian Portuguese usually does not need nós here.

So both are correct:

• Precisamos proteger a natureza.
• Nós precisamos proteger a natureza.

Adding nós can give extra emphasis or clarity, but it is not necessary.

After precisar when it means to need to do something, Portuguese normally uses an infinitive verb.

So the pattern is:

• precisar + infinitive

Examples:

• Preciso estudar. = I need to study.
• Precisamos proteger a natureza. = We need to protect nature.
• Eles precisam sair. = They need to leave.

So proteger stays in the infinitive because it is the action that is needed.

This is a very common question.

Portuguese uses precisar in two main ways:

1. precisar + infinitive = to need to do something

   • Preciso dormir. = I need to sleep.

2. precisar de + noun = to need something

   • Preciso de ajuda. = I need help.

In your sentence, the speaker needs to protect, so Portuguese uses:

• precisamos proteger

not:

• precisamos de proteger in normal Brazilian Portuguese

That version with de + infinitive is associated more with European Portuguese.

Here, a is the definite article meaning the.

• a natureza = nature / the natural world

In Portuguese, nouns often appear with an article where English may or may not use one. In this sentence, a natureza sounds natural and standard.

Also, natureza is a feminine noun, so the article is a, not o.

Yes. Natureza is a feminine noun in Portuguese.

So it takes feminine articles and adjectives:

• a natureza
• a bela natureza
• a natureza brasileira

This is something you just learn with the noun, since grammatical gender does not always match English logic.

A rough pronunciation guide for an English speaker is:

preh-see-ZAH-moos proh-teh-ZHER ah nah-too-REH-zah

A few helpful notes:

• s in precisamos sounds like z between vowels
• g in proteger sounds like the s in measure
• the stressed syllable in precisamos is za
• the stressed syllable in natureza is re

A more natural Brazilian flow would connect words smoothly: Precisamos proteger a natureza.

Portuguese does not use a separate word equivalent to English to before the infinitive in this structure.

English:

• We need to protect

Portuguese:

• Precisamos proteger

The infinitive form proteger already expresses the idea of to protect, so no extra word is needed.

Yes. Proteger is used very broadly, much like protect in English.

It can mean protecting:

• people: proteger as crianças
• places: proteger a floresta
• ideas or values: proteger a liberdade
• the environment: proteger a natureza

So it is a very common and flexible verb.

No, that would mean something different.

• Precisamos proteger a natureza. = We need to protect nature.
• Precisamos da natureza. = We need nature.

In da, you have de + a contracted:

• de a → da

So precisar de means to need something, while precisar + infinitive means to need to do something.

It is neutral and completely natural in everyday Brazilian Portuguese.

It works in many situations:

• conversation
• school writing
• campaigns
• presentations
• environmental slogans

It is not slangy, and it is not overly formal. It is a very standard sentence.

Yes, but the original order is the most natural and standard:

• Precisamos proteger a natureza.

You could also say:

• Nós precisamos proteger a natureza.
  This adds the subject we for emphasis.

Other changes are possible in special contexts, but they may sound more marked or literary. For most learners, the basic order is the best one to use.

Put não before the verb:

• Não precisamos proteger a natureza.

Grammatically, that means We do not need to protect nature.

Be careful: that is different from saying We must not protect nature, which would be a different idea. So the negative changes the meaning a lot.

Yes, precisar is a regular -ar verb.

That makes it easier to conjugate:

• eu preciso
• você precisa
• nós precisamos
• eles precisam

So precisamos follows a normal pattern, which is helpful for learners.