What was he doing ______ his father _______ back?A. while; came B. when; came C. when; was coming
—Your city looks beautiful!—Yes.Lots of trees and grass________last year.
Who were the shoes with special heels invented________?
—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.