Choose the appropriate words to complete the sentences

1. Easter is a spring [holiday|festival].
2. Can you tell me [what|that]we are doing here?
3. I am not sure [why|when] John is here.
4. Ask them [where|what] we are going.
5. I don't know [when|what] he will come.
6. — I don't know [whose|which] pets they are. / — I think they are Mary's.
7. The woman [who|whom] is standing under the tree is my aunt.
8. I don't understand [who|that] you are talking about.
9. George is the boy with [who|whom] I play football every week.
10. This is the farm [whose|which] name is «Old Oaks».
11. This is my real [wish|witch] to you.
12. [Ouch|Oops], my hand! It hurts!
13. When I go abroad, I always send [postcards|greeting cards] to my parents.
14. I am never afraid of [anybody|nobody].
15. People [celebrate|decorate] their houses on New Year's Eve.