World Expo 2010 Shanghai China, a grand-scale global event, has ______ the significant theme “Better City, Better Life.”

Have you found your English book? — I am not sure ____ I could have left it.

请选出以下各项中交际语言运用得体的一项（ ）

I don’t want to cooperate with _________ is different from me in character.

No sooner __________ these words than the warden hithim on the head with the soup spoon.