Our classroom is very dirty ,let’s _____it_______.

This is my good friend(朋友).—________ name is Tony.

What’s _______number of school in the city? —–I’m not sure ,but I know there must be _______ number of schools in it.

You made many mistakes in your English exams. What will you ___them?

“Underground” is the only word in the English language _____ begins and ends with the letters “und”.