Поставьте глаголы в скобках в форму герундия:
1. I must finish this work before (go) home.
2. He entered the room without (knock).
3. She has a very good habit of (get) up early.

1. going2.knocking (на счёт этого не уверена)3.getting

1. I must finish this work before going home.2. He entered the room without knocking.3. She has a very good habit of getting up early.