mine
In Italian, the word 'mio' is used to express possession, similar to the English word 'mine'. It is used when the possessor is a masculine singular noun. For example, 'Il mio libro' translates to 'My book' in English.
Where is my cat?
Here, 'mio' is again used to indicate possession, expressing relationship to the speaker. 'Gatto' is the word for cat, so 'mio gatto' translates to 'my cat'. The sentence is a question, inquiring about the location of the speaker's cat.
My grandfather is kind
This sentence uses 'mio' to express a familial relationship. 'Nonno' means 'grandfather', and 'mio nonno' translates to 'my grandfather'. The sentence describes a personal characteristic of the speaker's grandfather, being 'gentile' (kind).