Many a student  _____ that mistake before.

 The number of people present at the meeting _______ two hundred and a number of them _______ from the countryside. 

 ______children whose parents had died in the earthquake ____ sent to live with families in other cities.

There are usually 28        in a person’s mouth, so we should listen to the doctor’s ______ to protect（保护）them.

Mike, together with his parents, ________ going to the countryside to see his grandparents next week.