1.Are there many students at the lecture today?There aren't many students at the lecture today.
2.Is there a blackboad in front of the students desk?There isn't a blackboad in front of the students desk.
3.Are there several kinds of the left?There aren't several kinds ot the left.
4.Is there a window on the left?There isn't a window on the left.
5.Are there some tables on the wall?There aren't any tables on the wall.