В каких случаях ставится артикль "the"?

1. I --- scared at the cinema last night.
1) am 2) was 3) were
2. Hello!! We --- happy to see you. You look good.
1) are 2) was 3) were
3. Seva and Taras --- bored at the last lesson.
1) are 2) was 3) were
4. My mother --- a doctor. Sshe works in a hospial.
1) is 2) was 3) were
5. There --- a cake in the fridge. Where is it now?
1) is 2) was 3) were
6. I --- hungry. Is there anything to eat?
1) am 2) was 3) were

поясните, пожалуйста: в каких случаях ставится (is, are), а в каких (was, were)

......no letter for him