Can you please check the following statements with me?

Thank you very much.

1.I suggested to my mum what she should buy for my father as a Christmas present.
2.My dad made (prepared) the Christmas lunch.What did he prepared for lunch?
3.On Epiphany I stayed all day with my family.
4.How many hours did it take you to finish the exercise? How long did it take..
5.Frequency adverbs are placed (?) between the subject and the main verb.
6.I played a lot of songs on my guitar.
7.On the following (the next is also correct) day I wrapped up the presents for my family.
8.I went to my cousin’s house and I exchanged presents with his family.
9.I went to my grandparents’ house (can you omit the word house?) for lunch.
10.We went to our parish because our parents were waiting for us there.
11.These Christmas holidays were really exciting because I enjoyed myself with my friends (?)

2 answers

what am i checking for?
My dad prepared Christmas lunch. (I don't think you need the)
What did he prepare for lunch?
I went over to my grandparents for lunch.
How long did it take you to finish the exercise?