21.  First, we must deal with the pollution, Second, population control must be done immediately.

22.  Some people would be at a loss to deal with it.

23.  What should we do to deal with such thing ?

24.  How can we deal with the shortage of fresh water, the first thing is that we must save water .

25.  What can we do to deal with such problem ?

26.  Secondly, we should control and deal with the pollution, protect our fresh water resource.

27.  How can we deal with such serious situation?

28.  So we have to deal with the problem.

29.  With the help of the socience , we can deal with this question completely.

30.  In addition, we must deal with the pollution.