Finish the second sentence in such a way that it means exactly  the same as the as the sentence given:
1. Don't drop litter at public places or natural landscapes.
You mustn't..................................................................................
2. Oranges are cheaper than apples.
Apples....................................................................................................
3. I think Nha Trang City is more exciting than Phan Thiet City.
In my opinion, Phan Thiet City is..................................................................
4. They don't allow tourists to cross the desert alone.
Tourists mustn't...............................................................................
5. It' s necessary for travellers to make a reservation.
Travellers must.........................................................................................
6. There are life vests for all the passengers on this cruise ship.
They have..................................................................................................
7. Their rule is wearing a swimsuit in the pool.
People must................................................................................................
8. Not many people can book a trip to explore the cave.
Only a..............................................................................................................
9. Not many people can understand her lecture.
Only................................................................................................................
10. It is wrong of us to throw rubbish.
We mustn't throw rubbish.