6. I think he (come) tomorrow
7. Who (cook) breakfast in your family?
8. He (not/know) Spanish
9. Why you (smell) those flowers? They are plastic

6I think he will come tomorrow.
7who cooks breakfast in your family?
8he doesn't know Spanish?
9why are you smelling those flowers?
they are plastic.
в 9 предложении smell переводится-нюхать.поэтому present continuous.