I can't decide which one of the following sentences is correct and which one is not and why. Please help. Thank you
1- I wouldn't have the first prize unless I trained hard.
2- Unless you had studied hard, you wouldn't have got high marks.
3- Gamila wouldn't have bought the new car unless she had saved money.
4- I wouldn't have been able to do it unless she had helped me.
5- Unless you had told me about Rasha's new dress, I wouldn't have noticed it.
6- Unless my sister had been born, I wouldn't have had anyone to play with when I was a child.
7- I wouldn't have reached this good level unless she had helped me.
8- Unless he had had money, he wouldn't have moved into a large house.