It is written clearly in the requirements that all passengers _______ check onto board thirty minutes before the plane takes off．

Is it John that is being scolded in the manager’s office?
No. It ______ be him. I saw him on the way just now.

It is a common practice in China that the bride at the weeding ________ be dressed in red to ensure good luck.

Living in a fast-paced world, we                  get left behind if we stop learning.

-Was the United State of America founded on July 4^th, 1776？
--You _________  be right but I need to check it in the history textbook anyway.

The light in his office is out. He_________ left for home.

--Has Mr. White arrived, Tom?
--Yes, sir. _____ he come in to see you right now?

---What do you think is the matter with your car?
---Well, it _____ start at all. I mean I turned the key and nothing happened.

It was playing video games that took the boy too much time that he          have spent learning．

One of our rules is that every student ______ wear school uniform while at school.