I need quick help, I'll be very thankful.

3. School
4. Post office
5. Museum
6. Hospital
7. Sports centre
8. Bank
9. Cinema

1. That (“picture” is singular)
2. These (“painkillers” is plural)
3. This (“book” is singular)
4. Those, these (assuming that they are in possession of the letters but not the stamps)
5. That (the bus is not close to the subject)
6. Those (because it’s in past tense)

1. The, -
2. The, -, -
3. A, the
4. The
5. -
6. An
7. -, -
8. The
9. The
10. -, -

I hope this helps!