There are about more than five ___________ “left-behind” students (留守学生) in China.

Teachers often tell their students _______ across the road when the traffic light is red.

Thank you for your help, Linda. You made ________ possible for us to finish the work in time.

____the book if you are free, and you will learn a lot about how to study English .

He goes back to our school to visit his teachers every year. —____________.