7. If you don't try your best, you can't run fast.
8.  If you didn't live in the dormitory, you couldn't annoy me.
9. If the young girl doesn't stop smoking, she won't be healthy.
10. If people didn't know you, they wouldn't give you some precious information.

7) You can't run fast unless you try your best 
->If you don't try your best, you can't run fast.
8) Unless you lived in the dormitory, you could annoy me.
->.If you didn't live in the dormitory, you couldn't annoy me.
9) Unless the young girl stops smoking, she won't be healthy.
->.If the young girl doesn't stop smoking, she won't be healthy.
10) Unless people knew you, they wouldn't give you some precious information.
If people didn't know you, they wouldn't give you some precious information.