-Hey, Jack! I’ve worked on this math problem half an hour ,but it’s got me nowhere. Could you give me a hand ?- ______ . I’m good at math.
It’s a good song, _____ the lyrics(歌词)are not good enough.
—Do you know him? —I’m sure I’ve seen him _____, but I can’t remember the right place.
What can we students do _____ the environment?
—How long have you lived in this town? —_____ 2001.
There are five people in the room, but I know _____.