Thank you very much for your corrections!
Can you help me checking these other two paragraphs?
1) Last summer at my friend’s house, before a party, his dog was closed in a room where there was a lot of food for the dinner.(Better: the accident occured at a friend's house before a party) The dog jumped onto the table and ate some of it, then, while he was eating my friend’s dinner, he knocked a box of eggs, that fell off the table and smashed on the floor. Eventually, my friend found out the disaster and he had to call off the party.
2) Last week I went to a mountain resort and I saw a man who tried to jump onto the rail with the snowboard but he fell off and slid down. Afterwards the mountain rescue came over to help him. While they were coming, an avalanche came down the mountain and all the people were buried under the snow.
Thank you
1 answer
There's a run-on before "then" -- how will you fix it?
...my friend discovered the disaster...
2. Delete the second "I" and put a comma after "snowboard."
comma after the second "mountain"
Have you ever read the link I've posted several times about the use of commas? You are still leaving out commas needed after introductory phrases/clauses and in compound sentences. Why does this continue?
http://grammar.ccc.commnet.edu/grammar/commas.htm
See #s 2 and 3.
Also the information I've posted before about run-ons and how to fix them:
http://grammar.ccc.commnet.edu/grammar/runons.htm
There are 4 quizzes at the bottom of this webpage. You should working on getting them 100% correct so you don't keep making this particular error.