Thank you very much for helping me. Here are some more sentences I'm not sure of.

1) I like wearing casual clothes such as jeans and T-shirts. Today I’m wearing a polo/crew-neck/V-neck t-shirt (are all alternatives possible?)
2) This summer my sister went through a very bad period since her boyfriend died in a motorbike accident. He was taking a bend at high speed when he lost control of the vehicle and crashed into a lorry.
3) I went to a scout (?) summer camp in June.
4)Can you say: “I’m more childlike than my age” OR I’m immature for my age.
5) I always get good marks at school. My average mark is very good. I’ve never got a failed.
6) I went camping in Sicily. I visited the Valley of the Temples.
7) I’ve gone (or been?) horse-riding twice. I’m only a beginner in horse-riding.The meals at the hotel were very good.
8) I was playing in a fistball tournament when I fell and broke my arm. I was taken to hospital and the surgeon put it in plaster. (OR I had it X-rayed and plastered). My arm was in plaster for a month (also: I had my arm in plaster.

1. yes

4. yes
5. I've never gotten
7. either
8. I was taken to the hospital

5. instead of "marks" you might use "grades" also

Sra