keep an eye on her
Let's keep an eye on her.
Mas o velho Tokuemon ficou de olho nela.
But old Tokuemon kept an eye on her.
— Yojimbo, o Guarda-Costas (1961)
A vizinha disse que ficará de olho nela.
The neighbor said she would keep an eye on her.
— O Lamento (2016)