Помогите с заданием!

Измените залог в следующих предложениях

1. The speaker stressed the importance of the Congress.
2. This actor will play the part of Hamlet.
3. The students have learnt a lot of new English words.
4. The director himself answered the phone.
5. Somebody recommended me to see that doctor.
6. They had eaten all the dinner before they finished the conversation.