the secret of nature, the youngscientist has little time for entertainment

Why are we always having examinations?— _____ whether we have grasped the knowledge in every subject.[ ]

When are you _____ your next exams? —– Next month.

How do the shops make money ifthey sell at such low prices?— Manufacturers, it seems, are willing to bring down prices____ big volume purchases[ ]

When will your new book ________ —Probably in December．