Translation:The girl drinks the coffee, the milk or the tea.
I believe it's the difference between the indefinite and definite form - you use the ua ending for the definite form - "THE coffee" - and cafea for the indefinite form - "A coffee" or just "coffee".
I just suddenly realised that maybe you meant what words use the ending rather than what the ending means...
In that case, it depends on the noun and its declension. There are a number of different endings for different types of nouns, and it's a complex matter. There are rules, but there are also lots of exceptions as well.
https://en.wiktionary.org/wiki/Appendix:Romanian_nouns is a decent place to start but grammar is a complex topic.
Why "girl" can`t drink the coffee, I mean why only "the girl" can do this?
In this respect it is similar to English (in others, not). You can't say correctly: "girl drinks coffee". Only "a girl" or "the girl" or "some girl".
It's the ending of "Fata" - the a means it's the definite form - "The girl". To say just "girl" you'd have to use the indefinite form "Fată" but that probably wouldn't be any more correct in Romanian than it is in English. I would imagine you would need to use "O fată" for "A girl".
Shouldn't it be "the girl drinks coffee, milk or tea"? It makes much more sense, in English at least.
Both make sense; "Which of these beverages does the girl drink?" "The girl drinks the tea, the coffee and the milk, but not the juice or the lemonade."
The simple fact is that if you wanted to say what you've suggested, you need to use the indefinite article, not the definite article. So the sentence would be instead: "Fata bea cafea, lapte sau ceai."
Why does it have to include the in front of each item listed when in English, we don't do that?
Technically there's a subtle difference between the two.
This sentence uses the definite form of coffee, milk and tea - meaning this specific coffee, milk and tea. What you are suggesting would be the indefinite form - just general coffee, milk and tea. The difference is subtle, but it's important and in this case, the sentence is clear, it's using the definite form, so it needs to use "the" in front of all three drinks.
I am confused where to use bea and where to use beau ....plz help ???
"Bea" is 3rd person singular present tense (that is, "he/she drinks") and "beau" is 1st person singular present tense ("I drink") or 3rd person plural present tense ("they drink").
The full present tense conjugation of "a bea" (that is, "to drink") is as follows:
eu beau (I drink - 1st person singular)
tu bei (you (singular) drink - 2nd person singular)
el/ea bea (he/she drinks - 3rd person singular)
noi bem (we drink - 1st person plural)
voi beţi (you (plural) drink - 2nd person plural)
ei/ele beau (they drink (all male or mixed groups/all female groups) - 3rd person plural)