Can you please check my sentences? Thank you.

1) I've been out for lunch.
I've written a lot of tests at school.
I've spent a lot of time revising for my English test.
2) I've bought a new lap top computer.
I've participated in an athletic competition.
3) I've participated in a cross country skiing competition.
I've had luch at the school's canteen.
I've been to France for my holidays.
I've been to France on holiday.
4) Where have you been on holiday?
I've been on a one-day school trip in the mountains.
I've had to look after my sick cat.
I've written a lot of tests.
I've taken a computer driving licence course.
5) I've had fun with both my friends and family.
I've just moved into a new house. It's a flat on the first floor of a three-storey building.
6) I've gone swimming
I've trained for a swimming competition.
I've written many emails to friends.
I've had a lot to do for school.
What your first piece of news?
7) Have you got any good news?
My first news is that I've just come back from my holiday.
8) I've had to help my mum cook meals.

All look good. One spelling item, though: "laptop" is usually spelled as one word, not two.

Here are the corrections to your sentences:

1) I've been out for lunch.
I've written a lot of tests at school.
I've spent a lot of time revising for my English test.

2) I've bought a new laptop computer.
I've participated in an athletic competition.

3) I've participated in a cross-country skiing competition.
I've had lunch at the school's canteen.
I've been to France for my holidays.
I've been to France on holiday.

4) Where have you been on holiday?
I've been on a one-day school trip in the mountains.
I've had to look after my sick cat.
I've written a lot of tests.
I've taken a computer driving license course.

5) I've had fun with both my friends and family.
I've just moved into a new house. It's a flat on the first floor of a three-storey building.

6) I've gone swimming.
I've trained for a swimming competition.
I've written many emails to friends.
I've had a lot to do for school.
What is your first piece of news?

7) Have you got any good news?
My first news is that I've just come back from my holiday.

8) I've had to help my mum cook meals.

Overall, your sentences are grammatically correct, but there are a few minor corrections needed. Keep up the good work!