--What you for your vacation? --I plan to visit my grandparents.
—A number of students________in the dining hall.—Let me count.The number of the students________about 400.A.are;isB.is;areC.are;are
She put back the book she had taken________mistake.
________it rains heavily,they go on working outside.
What________is the most helpful invention?
The dinner didn’t start________all the friends arrived.