Object + Infinitive constructions

Hello there!
We're supposed to do this grammar exercise on, as you may have already guessed, the above mentioned subject. The exercise instructions, however, simply state to rewrite the following sentences using object and infinitive constructions.
E.g:
1. He must not enter the house. I don't want...
2. I saw that he entered the house.
3. She said that she was busy.
4. You ought to do your homework now. I want...
As there were no examples or further instructions provided to us on what, exactly, we're expected to do, I'm not sure how to rewrite these sentences. Does anybody have an idea?