Trees are very important to our environment. They can stop wind from blowing the earth away.
—Peter looks sporty. —Yes. He is the ______runner in my class.
We won’t go sightseeing if ____ tomorrow.
—The classroom is ____ clean ____ it was yesterday. — Sorry, I forget to clean it.
I was just falling asleep ____ there was a loud knock at the door.
----Can you tell me if he ________ ? ----If he _________, I will call you.