Tom moved to this town in 1994. (Simple Past - completed action in the past with a specific time)
My friend was in Canada two years ago. (Simple Past - completed state in the past with a specific time)
I haven't been to Canada so far. (Present Perfect - experience up to the present)
But I have already travelled to London a couple of times. (Present Perfect - experience up to the present)
Last week, Mary and Paul went to the cinema. (Simple Past - completed action in the past with a specific time)
I can't take any pictures because I haven't bought a new film yet. (Present Perfect - action not completed up to the present)
Did they spend their holiday in New Zealand last summer? (Simple Past - question about a completed action in the past with a specific time)
Have you ever seen a whale? (Present Perfect - question about an experience at any time up to the present)