When he is invited to a party， he is always making trouble or upsetting others．-Just as people who know him say，______．

I think it unwise to live ______ one’s income, as is the case with a lot of young people today, who often turn to their parents for help

The professor, _____ some of hisassistants, _____ to attend our discussion this afternoon.

It is dangerous ____ you ______ a close look at the tiger in the zoo.

in a spare moment at the weekend or _____,it really doesn’t matter