15. --- Who are the teenagers gathering at the school gate? --- Well, if you _____ know, they are all my visiting students.
China Daily is __________ a newspaper; it keeps us in touch with the world.
Mr. Stevenson is great to work for—I really couldn't ask for a __________ boss.
There is a big library in our school. There are more than twice __________ five years ago.
—What does the model plane look like? —The wings of the plane are __________ of its body.
At a rough estimate, Nigeria is __________ Great Britain.