Was it ______ he was playing volleyball on theplayground_________ he got hurt

—Will you lend me some paper?—Sorry, mine ______.[ ]

There are lots of _____that students have to follow in school.

Some people disagree with the idea _____digital textbook will improve education quality while the traditional textbookis out of date.

There ______a number of books in our school library. The number ofbooks________getting larger than last year.