Spend . Expend . Cost . Pay
Every year, she spends a lot of money on clothes.
We’ve just spent 1.9 million on improving our computer network.
I’ve spent an hour in the station waiting for the train.
各位瞅仔细了，spend [money] on doing sth.但是spend [time] doing sth.这就是区别。雅思考官各个鹰眼犀利，可别范怂。
My sister always spends ages in the bathroom.
I want to live in a dormitory to spend time with my school friends.
For the past month, he’s spending all the energy trying to find a job.
Her anger soon spent itself (=stopped). 她只生了一会气。
You expend so much effort for so little return.
Governments expend a lot of resources on war.
I cost 30 dollars for the board game. X
The board game costs me 30 dollars.√
I spend 30 dollars for the board game.√
One costs more money running a business than buying a house. X
Running a business costs more money than buying a house.√
It costs more money to run a business than to buy a house.√
(因为这句话的主语是不定式to run a business，所以它被放在谓语和宾语后面，，主语用it代替)
●pay的用法。pay强调“付款”，也有pay [money] for sth.这样一看就懂的用法
You have to pay four dollars for each hamburger.
Mum paid for my driving lessons./Mum paid me for the driving lessons.
Ray paid some kids to wash his car.
Ray paid the kids 10 dollars to wash his car.
A savings plan that paid six percent interest
It pays to be honest. (= It is good to be honest)
William is now paying the price for his early mistakes.
I decide to pay my folks a visit this weekend.