15.A number of books ______ been stolen from the library since the beginning of this term and the number _____ as large as 500.
It is that he hasn’t .
Don’t worry! Philip is quite used to in such busy streets as this.
The teacher was angry about his being late for class, but he behaved ______ nothing had happened.
Candidates ______ remain in their seats until all the papers have been collected.
—Excuse me, Dad, but I’m going to the club to meet my friends in the football team. —OK. ______