can/ can't/ have to/ don't have to

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Complete with can/ can't/ have to or don't have to.

1. You smoke in the classroom, but it's okay to smoke outside.
2. You buy expensive books to learn English at the Language Institute.
3. If you don't want to buy books, you borrow books from the library.
4. You study hard if you want to pass the final exam.