Not only the students but also their teacher _______ about the four people.
These young trees must ______.
Many Chinese students found______ difficult to learn English grammar.
---Where are you going, Jack? --- My hair is too long. I’ll have it _______.
---Who is the tallest boy? ---It ______ be John.. John is of medium height.
---Is your father a teacher? ---Well, he ______. But now he works in a bank.