IV.
1.unhappily
2.childhood
3.excited
4.succesfully
5.competitors
6.flights
7.entertainment
8.behaviors
9.proud
10.uncomfortable
V.
1.A: said->saying
2.B: rung->rang
3.A: It not difficult->It is not difficult
4.B: how explain->how to explain
5.B: greatly->great
6.B: take->took
7.B: since->from
8.B: believe->believed
9.D: does Jane->did Jane
10.B: doing->to do
VI.
1.Unless the weather is bad , we will go away
6.The date of the meeting will have to be changed again
7.Hoa isn't as good at English as Lan
8.The water wasn't warm enough for the children to swim in
9.You don't need to set off early
