The best way to differentiate the uses of "what" and "what" is by identifying the grammatical classification that each one can exercise.
However, as a general rule, taking into account the placement and even the meaning of such words in sentences can be of great help.
use of what
start of sentence: introduces question or indicates intensity.
mid-sentence: refers to something/someone that/whom has already been talked about at some point in the past.
Examples:
- What bang was that? (interrogative pronoun function)
- What heat! (intensity adverb function)
- that is the teacher what will give us math lessons. (relative pronoun function)
use of what
start of sentence: indicates annoyance, impatience, perplexity, anger, surprise, fright, etc.
mid-sentence: means "something", "something". It is accompanied by the indefinite article "a".
end of sentence: ends questions.
Examples:
- What?! You must be kidding! (interjection function)
- This boy has a what of charming. (noun function)
- children are in need of what? (interrogative pronoun function)
when to use what
For the use of “what” to be applied correctly, it is necessary to understand the grammatical function it plays in the sentence.
The "that", without an accent, can have the following grammatical classifications: adverb, conjunction and pronoun.
Adverb
The adverb "that" is used to indicate intensity.
Examples:
- What a beautiful beach!
- It's cold!
- What a beautiful dress!
- How happy to see you again!
- What a difficult test!
Conjunction
As a conjunction, "that" links different elements of a sentence, and can indicate: explanation, cause, purpose, concession, integration, comparison, consequence and time.
Examples:
- He said he would come. (explanation)
- Since he was late, he decided not to enter. (cause)
- He hid his face so no one would see him cry. (goal)
- Even if it was free, I wouldn't go. (concession)
- Hope he's not late. (integration)
- Luan is older than Miguel. (Comparation)
- We walked so much that I got pain in my legs. (consequence)
- As soon as I get there, I'll call you. (time)
Interrogative Pronoun
The interrogative pronoun "that" is used to introduce questions.
Examples:
- What time is it?
- What difference does?
- What phone is this?
- What car did you buy?
- What Day is Today?
Relative pronoun
When exercising the function of relative pronoun, "that" refers to something or someone that or who has already been mentioned before.
Examples:
- This is the computer I just bought.
- Tomorrow my niece arrives from Brazil.
- That's the building I told you about.
- The book I want is on sale.
- That was the question he asked me.
when to use what
An effective way to understand the use of "what" is to know the grammatical functions it performs.
The "what", with an accent, is used as an interjection, pronoun and noun.
Interjection
The interjection "what" is used to indicate amazement, admiration, anger and surprise, among others.
Examples:
- What? I can't believe you booked our dream trip! (amazement, admiration and surprise)
- What? Did he really say that? (amazement and surprise)
- What?! Who gave you permission to go through my things? (anger)
Interrogative Pronoun
The interrogative pronoun "what" ends a question.
Examples:
- What did Paulo call you for?
- What are they talking about?
Substantive
When used as a noun, "what" represents something indefinite or something that is difficult.
Examples:
- The culture of that country has something attractive. (something undefined)
- Learning math isn't impossible, but it has its things. (something difficult)
The words "what" and "what" can also be accompanied by "o". “What” and “what” are expressions formed by two separate elements.
The addition of “o” does not change the meaning; it only gives emphasis; Spotlight; highlight.
As far as usage rules are concerned, "what" is used at the beginning of sentences and "what" at the end.
Examples:
- What was there?
- What is he in the backyard doing?
Important
The form "what", with the elements together, does not exist in the Portuguese language and, therefore, is incorrect.
You may also be interested in: Functions of the "what" and Use of why, why, why and why.