spend:(花钱+on、花时间+in)1、sb. spend some money on sth. eg.I spend 1 yuan on the pen.2、sb. spend some time in doing sth. eg. He spends two hours in finishing his homework.3、sb. spend some time in (doing) sth.(重点) eg.Though I spend much time in math ,I still got "c" for it. (误区:一般人认为表sth.的"math"前应加on,但是这里是把math前的动词省略的缘故造成的误区。判断方法:表花时间做某事用in,花钱买某物就用on,这个应该很快就能判断出来了,就不会造成误选,这是考试最常考到的,要注意啊)cost(+to do)1、sth. cost sb..(宾语形式) some money.(花钱买某物) eg.This book cost me 10 dollars.2、It cost sb.(宾语形式) some time to do sth.(花时间做某事) eg.It cost me 2 hours to finish the homework.pay(+for)1、sb. pay some money for sth.( 某人花钱买某物) eg: I pay 10 dollars for this book. 希望以上归纳对你有用啦。。。