Which sentence uses the tense and time expression correctly?
The gallery has opened six months ago.
The gallery opened six months ago.✓Respuesta correcta
The gallery is open since last autumn and remains open now.
The gallery opened since last autumn and still operates today.
Explicación
The gallery sentence is correct because ago locates the opening at a finished point in the past. The closest distractor combines the present perfect with ago, but that finished-time marker requires the past simple.