Поставить предложения в вопросительную форму и дать ответ. 9)you have known his parents for many years. 10)both sisters had already left when i returned. 11)now machine has recently come from germany.

9) Do you know his parents?
Yes, I have known them for many years

10) Did both sisters leave?
Yes, right when you returned

11) Where has machine come from recently?
From Germany

9) Have you known his parents for many years? Yes, I have.
10) Had both sisters already left when I returned? No, they hadn't.
11) Has the new machine recently come from Germany? Yes, it has.