Past Simple, Present Perfect or Present Perfect Continuous.

He (send) his letter yesterday.
I (not/watch) this video yet.
We (study) in this classroom since September.
Where’s Pete? I (not/see) him since Monday.
It (snow) since 12o’clock.
He (buy) a new suit last week.
The teacher (ask) us for two hours.
I (listen) to a new disk. I’m enjoying it.
Tom (go) to London two days ago.
There (be) a lot of people in the restaurant last night.