Помогите составить предложения Ski,well,my sister,my brother,not ski, well

Ski:
I dont like riding on skis, because I think it is very dangerous.

Well:
You did this exam very well.

My sister:
My sister won the competition in Mathematics and won a medal.

My brother:
My brother isnt good at studying, that is why I always help him with his homework.

Not ski:
When we went to a ski centre, I did not ride on skis because I was scared to fall.