The number of people invited ______ fifty, but a number of them ______ not seen at the meeting.
People have planted a lot of trees and grass in order to ____ wind and sand in the desert.
Read the passage and correct the mistakes, ______.
—What do you think of the concert given by the famous Hong Kong singer? —Not so good.In fact, it _____ to be a great disappointment.
Sometimes, the _____ of humor in this country causes misunderstanding in other countries.
I was out of my village at the time, so I don’t know exactly how it_______about.