(年北京市西城区高三5月二模试题)31. A person who has never tasted bitter won’t know ______ sweet is.
---Can I use your dictionary? ---______.
Mary is an honest girl; I say it, ________I don't like her.
I prefer to buy a new TV rather than ________ it.
He doesn't know_________ the work by himself.
Oh, boy, why are you killing your time this way? Can’t you find something ________ doing?