Questions & Answers about Oni ne mogu igrati tenis.
Why is the negation written as two separate words (ne mogu) instead of one?
In Croatian, the negative particle ne is usually written separately from the verb. You might remember exceptions from earlier lessons like nisam (I am not) or nemam (I do not have), but the verb moći (can) follows the regular rule. So, "they cannot" is always written as two words: ne mogu.
How do we link the verbs mogu (can) and igrati (to play) together?
Just like in English, you use the conjugated form of the modal verb (mogu - they can) directly followed by the basic dictionary form, or infinitive, of the action verb (igrati - to play). You do not need any extra connecting words between them.
If mogu already means "they can", do we really need the word Oni (they)?
Not strictly! Because the verb ending in mogu already tells us the subject is "they", you can safely drop the pronoun. Saying Ne mogu igrati tenis is perfectly natural. Including Oni just adds a little extra emphasis, like saying "They are the ones who cannot play tennis."
Why doesn't the word tenis change its ending since it's the object of the action?
It is indeed the object, which means it is in the accusative case. However, tenis is a masculine noun that represents an inanimate object (not a living being). For non-living masculine nouns, the accusative form looks exactly the same as the basic dictionary form.