No, it isn't.Our classroom is dirty,because classmates are not cleaning the claassroom. Also, the lunch is too small. So, we have to go to downstares. = No, it isn't. Our classroom is dirty because my classmates are not cleaning the classroom. Also, the lunch area is too small, so we have to go downstairs.

*Ahh I see. If the room is dirty, you cannot focus on studying.