1. 用方框中所给短语的适当形式填空。

get lost, on one's own, pay attention, set off, be careful of

1. （1） We should to our teacher when we have classes.
3. （2） If you go into the forest alone, you may .
5. （3） My uncle will to go to Shanghai tomorrow.
7. （4） When I travel with my family, my little brother left .
9. （5） the holes, you may fall down into one of them.