Thank you again for your last corrections!

Can you help me check these sentences please?

1) I had planned to do a lot of things during my Christmas holidays but unfortunately I didn't get around to doing them all.
( and NOT I had no time to do all of them)
2) I decided (?) to rest after the hard work at school (and NOT the stress accumulated at school?)on my first days of holiday
3) On Boxing Day I left for "St Moritz", a ski resort in the Alps where I celebrated New Year's Day with my friends
4) I stayed there till January 28.
5) Eventually,it was a good Christamas (OR All in all, I spent a good Christmas time or I enjoyed my Christmas holidays)
6) How are the possible prepositions with "Christmas holidays"
During/on/over my Christmas holidays I stayed at home (in my IS WRONG?)
7)On Christmas Eve I exchanged Christmas greetings with my relatives and we had dinner together.It is a tradition of (in?) my familiy because Christmas Eve is the day of my aunt's birthday.
8) On Christmas Day I stayed at home because I was ill and I went to bed right after midnight.
9) I finished my homowork on January 7 as I did not want to do any homework on the day before school began (or on January 8)
10) When the teacher saw the blown bulb, he got frightened and urged us to go(?) under our desks. A few minutes later he told us to go to our places and he continued his lesson again. (Is this version better?)

1) The sentence is grammatically correct and conveys the meaning accurately. However, if you want to express that you didn't have enough time to do them all, you could say, "Unfortunately, I didn't have enough time to do them all." This adds more clarity to the reason why you couldn't complete all the planned tasks.

2) The sentence is grammatically correct. However, if you want to emphasize that you needed rest specifically because of the accumulated stress from school, you can say, "I decided to rest after the accumulated stress from school." This makes the reason for resting more explicit.

3) The sentence is grammatically correct.

4) The sentence is grammatically correct. However, you can make it more clear by saying, "I stayed there until January 28th."

5) The sentence is grammatically correct. However, you can use the phrase "All in all" to indicate that overall, your Christmas was good. So, you can say, "All in all, it was a good Christmas."

6) The possible prepositions you mentioned are correct. You can use "during," "on," or "over" to indicate the time frame of your Christmas holidays. For example, you can say, "During my Christmas holidays, I stayed at home." However, using "in my" instead of "in" is incorrect in this context.

7) The sentence is grammatically correct. However, it would be more accurate to say, "It is a tradition in my family." This indicates that the tradition is present within your family.

8) The sentence is grammatically correct.

9) The sentence is grammatically correct. However, it would be more accurate to say, "I finished my homework on January 7th." This adds clarity to the completion date.

10) The sentence is grammatically correct. However, if you want to indicate that the teacher urged you to go under your desks, you can say, "he urged us to get under our desks." Additionally, the revised version you provided is better as it clearly indicates the sequence of events.