Помогите, пожалуйста!
напишите следующие предложения во множественном числе, изменяя также форму глагола to be:
1. This is my pen and that is your pencil.
2. This is our office and that is yours.
3. This is his desk and that is hers 
4. This is my book and that is theirs 
5. This is my letter and that is yours 
6. Is this is my book? 
7. Is that house yours? 

1)These are my pens and those are your pencils2) These are our offices and those are yours3)These are his desks and those are hers4)These are my books and those are their5)These are my letters and those are yours6) Are these my books?7)Are those houses yours?