—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
– What makes you so upset, Mr. Wang?– That John, a student in my class, ______ himself to computer games.
Don’t worry too much about ______ mistakes. They are ______ natural part of learning.
I wish you hadn’t given him my telephone number, but you .
You may use the room as you like you clean it up afterwards.
—Would you take this along to the office for me? -- .