---- What do you think of the book? ---- Oh, excellent .It is worth __________ a second time.
-Don't you think that her performance has made a sensation? -Who but you can be ________by that?
-Whose bag is this? -It's not mine. It must be________.
________everyone can hear the speaker,there is no ________in turning up the radio.
It's reported that a plane with five people ________crashed into the mountain several days ago.
He was just about to give up hope,________a good idea came into his mind.