—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
The police will have to the room for fingerprints.
once before, after your class I got my visa(签证). So thank you again.
Who is the man a blue shirt? I have never seen him before.
Here is my classmate ________ bicycle was lost yesterday.
The young doctor is determined to devote all his life to ________ the cause of cancer.