Breakdown of Она кладёт телефон в свою сумку.
она
she / it (for a feminine noun)
телефон
phone
сумка
bag
в
in / to (direction)
Questions & Answers about Она кладёт телефон в свою сумку.
Why does this sentence use свою instead of её for 'her'?
Свой means 'one's own'. Because the subject (Она) is the one who owns the bag, we use the reflexive pronoun. If the sentence used её (в её сумку), it would mean she is putting the phone into someone else's bag (another woman's bag).
Why is the ending свою and not своя?
The pronoun has to match the gender, number, and case of the noun it describes. Since the action is directed into the bag, the feminine noun сумка changes to the Accusative case (сумку). To match it, своя becomes свою.
Why are we using the Accusative case (в сумку) instead of the Prepositional case (в сумке)?
We use в + Accusative because there is direction or motion involved ('putting into'). If the phone was already resting inside the bag, we would use the Prepositional case to show a fixed location: телефон в сумке (the phone is in the bag).
What is the dictionary form of the verb кладёт?
It comes from the verb класть (to put, to lay). This verb changes its stem in the present tense, which is why you see an unexpected 'д' in forms like я кладу (I put) and она кладёт (she puts).