用英语解释下列句子初一题

1.What do you do that for?
why do you do that?
2.I think wasting time is foolish.
In my opinion,it is silly to waste time.
3.Can you tell me how I can get to the library?
do you know where is the library?
4.It took me an hour toget to the other side of the river.
getting to the other side of the river spent me an hour.