---Who is the tallest boy? ---It ______ be John. John is of medium height.
My sister ______ go to bed _______ my mother came back last night.
Mary’s grandpa is always ______ in the mountain village. He tells her he feels very______. So she’s going to visit him next week.
They argued _________ each other ________ the math problem yesterday.
__________ important for children __________ on themselves.
The book is for us to read.