I have a trouble about using articles (a/an/the)

[Assassin]

A:what would u like to eat?
B:I would like an apple, please.
-> In this case, both the speaker and listener know what is being talked about, even if it has not been mentioned before. So, why don't we use the ?

A:what fruit do you like to eat?
B:i like apples.

-> Why B didn't say an apple like the first case ?

 

[Anglika]

Welcome to the forums.

A:what would u like to eat?
B:I would like an apple, please.
-> In this case, both the speaker and listener know what is being talked about, even if it has not been mentioned before. So, why don't we use the ?

Unless there was only one apple available, B is saying he will take any apple offered.

A:what fruit do you like to eat?
B:I like apples.
-> Why B didn't say an apple like the first case ?

He is talking about the generic fruit. He could have said "an apple", but in this context where a general question about fruit is asked, the plural tends to be used.

.

 

[David L.]

B:I would like an apple, please.
-> In this case, both the speaker and listener know what is being talked about, even if it has not been mentioned before. So, why don't we use the ?

They know what is being talked about because both know what 'apples' are. That is the whole point of having language, of naming objects. But in your sentence, no specific apple has been previously mentioned. Look at this conversation:

She ( to grocer): May I have an apple please? (Buys the apple, walks away and takes a bite- it's bad inside. She returns to the grocer.) The apple you just sold me is bad inside.................
'an apple' because it's any apple of all the apples he has. Once she has been given it, it is a particular, specific apple - the one he sold her, so 'the apple'


A:what fruit do you like to eat?
B:i like apples.

-> Why B didn't say an apple like the first case ?
Because he is referring to apples in general, apples as a fruit, not just to one apple (an apple) and not to a very specific apple (I liked the apple grandma gave me this morning).

 

[David L.]

I'll take it easy and go off and have a cup of tea - you've got the groundwork covered!