I forgot to include the following sentences.

Thank you very much for your invaluable help.
1) I went to church for (the) Christmas Mass.
2) How many hours (or just: how long is possible) did it take you to get there?
3) How many days (or just: how long) did your holidays last?
4) For me a soup of the day (OR just: I'd like/I'll have a soup of the day, please.)
5) In the mountains there were my best friends (or better: My best friends were in the mountains, too)
6) I was invited to a party at a friend's house (but I was invited to or at a friend's house?)
7) Are you ready to order? Yes, please or Yes, I'd like an ice-cream (?)
8) Go under the arcades up to the (?) end of the road (or until you get to the end of the road?)
9) go through the underpass, or take the underpass?
10)Go on the sidewalk: the opposite is: go off the sidewalk
11) We burst some (and not "the") fireworks.
12) Go to the end of the main street and you'll see the cathedral on your right next to the town hall.
13) We returned to our houses (but we returned home)
14) We exchanged and unwrapped our presents (or gifts?)
15) We spent Christmas Day (and not "the" Christmas day?)
16) I spent time with my cousins taking photos to my little cousin.
17) We really had fun.
18) I celebrated New Year's Eve at a party with my friends. I toasted the new year with (?) my friend.
19 I waited for midnight mass (or the midnight mass?)
20) On 27th of March in the evening (and not on 27th evening?)
21) I stayed at home and I revised my homework for my first school day (after my Christmas holidays) OR I went over my holiday homework again?

1) I went to church for Christmas Mass.

2) How many hours did it take you to get there?
3) How many days did your holidays last?
4) I'd like/I'll have a soup of the day, please.
5) My best friends were in the mountains, too.
6) I was invited to a party at a friend's house.
7) Yes, I'd like ice-cream. (state flavor and size)
8) Go under the arcades up to the (?) end of the road (or until you get to the end of the road?) (Either)
9) go through the underpass, or take the underpass? (Either)
10)Go on the sidewalk: the opposite is: go off the sidewalk (Or "Don't walk on the sidewalk.")
11) We burst some (and not "the") fireworks.("set off some fireworks" would be better.)
12) Go to the end of the main street and you'll see the cathedral on your right next to the town hall. (Good)
13) We returned home.
14) We exchanged and unwrapped our presents (or gifts?) (either)
15) We spent Christmas Day....
16) I spent time with my cousins taking photos to my little cousin. (If you transported the photos to your cousin, this would be correct. If the cousin is being photographed, it would be "of my little cousin.")
17) We really had fun.
18) I celebrated New Year's Eve at a party with my friends. I toasted the new year with my friend. (good)
19 I waited for midnight mass.
20) On 27th of March in the evening.... If you know for certain that the month being described was March from previous information, then it does not need to be mentioned.
21) I stayed at home, and I revised my homework for my first school day (after my Christmas holidays) OR I went over my holiday homework again? (Either, depending on the previous information. If you are already talking about Christmas holidays, the phrase does not need to be included.)

I hope this helps.

1) To include the sentence "I went to church for (the) Christmas Mass," you can simply add it to your previous message or conversation.

2) To find out how long it took someone to get somewhere, you can ask the question, "How many hours did it take you to get there?"

3) To inquire about the duration of someone's holidays, you can ask the question, "How many days did your holidays last?"

4) If you want to request a soup of the day, you can say, "I'd like a soup of the day, please."

5) To rephrase the sentence, you can say, "My best friends were also in the mountains."

6) To clarify whether you were invited "to" or "at" a friend's house, you can ask, "I was invited to a party at a friend's house, right?"

7) In response to the question, "Are you ready to order?" you can respond with either "Yes, please" or "Yes, I'd like an ice-cream."

8) To give directions that involve reaching the end of a road, you can say, "Go under the arcades until you get to the end of the road."

9) When providing instructions involving an underpass, you can say, "Go through the underpass."

10) When instructing someone to use the sidewalk, the opposite would be, "Go off the sidewalk."

11) To properly express the sentence, you can say, "We burst some fireworks."

12) To give directions to the cathedral, you can say, "Go to the end of the main street and you'll see the cathedral on your right, next to the town hall."

13) To express the idea of returning home, you can say, "We returned home."

14) To describe the action of exchanging and unwrapping presents, you can say, "We exchanged and unwrapped our gifts."

15) To talk about spending Christmas Day, you can say, "We spent Christmas Day."

16) To explain that you spent time with your cousins and took photos of your little cousin, you can say, "I spent time with my cousins, taking photos of my little cousin."

17) To convey the idea of having fun, you can say, "We really had fun."

18) To describe celebrating New Year's Eve and toasting with a friend, you can say, "I celebrated New Year's Eve at a party with my friends. I toasted the new year with my friend."

19) To talk about waiting for midnight mass, you can say, "I waited for the midnight mass."

20) To state the date and time, you can say, "On the evening of the 27th of March."

21) To describe revising homework for the first school day after Christmas holidays, you can say, "I stayed at home and revised my homework for my first school day," or "I went over my holiday homework again."