The doctor was ______ immediately the little boy fell off a ladder and hurt himself.

, how depressed! I am bound to lose to him in tomorrow’scompetition.—Cheer up! In fact, he is___________thanyou!

The millions of calculations involved, had they been done by hand, _____ all practical value by the time they were finished

Are good friends. We are classmates.

下列各句中，加点的成语使用恰当的一句是(　　)