1．You have to wear a life jacket for protection (protect) in case you fall into the river.
2．It isn't wise to spend all your salary every month.Keep some money in reserve, just in case.
3．He's decided to get a look at the house and see whether it was worth purchasing (purchase)．
4．It's a pity that a lot of people didn't value the time.They waste their time doing(do) nothing useful.
5．With all his attention focused(focus) on his experiment, he has no time to spend with his family.
Ⅱ.单句改错
1．Although treating unfairly, he still worked very hard.treating→treated
2．All those concerning about the poor children should be thanked.
concerning→concerned
3．There is no wonder you're tired; you've been walking for hours.There→It
4．The temple is now in bad conditions.It needs to be repaired.
conditions→condition
5．Don't hurt this kind of animal any longer.It is endangering now.
endangering→endangered
