Rewrite the sentence so that its meaning stays the same

rewrite the sentence so that its meaning stays the same.
1 they intend to make this beach a clean and beautiful place again.
-> they plan ..................................................................................................................
2 the students started to collect old clothes for their charity programme.
-> the students have .....................................................................................................................
3 we make the air dirty because we use the car all the time.
-> if we use .................................................................................................
4 if i don't leave now, i'll miss my train.
-> unless i leave ..............................................................
5 i won't be able to do anything unless i have a quiet room.
-> if i don't have .........................................................................