Learn Turkish: O bir kutu açıyor.

The root of the verb is aç- (open). To make the present continuous tense (happening right now), we add a suffix. Since aç- ends in a consonant and its only vowel is 'a', vowel harmony rules tell us to use the connecting vowel ı, making the suffix -ıyor. Added together, we get açıyor. Because the subject is O (he/she/it), we don't need any extra personal endings.

The translation says 'He'. Could O also mean 'She' or 'It'?

Yes! Turkish does not have gendered pronouns. O can translate to 'He', 'She', or 'It' depending on who or what you are talking about. The context of your conversation will make it clear.

Why is the verb açıyor at the very end of the sentence?

Turkish generally uses a Subject-Object-Verb word order. Here, the subject O (He) comes first, the object bir kutu (a box) is in the middle, and the action açıyor (is opening) finishes the sentence.

Why is the word for box just kutu without any special endings?

Because he is opening a box (bir kutu), it is an indefinite object. In Turkish, we only add a specific object ending (which would make it kutuyu) when we are talking about the box. For 'a box', the word stays in its plain dictionary form.