spend,cost,take和pay都表示“花费”。
spend的主语必须是人。
(1)spend time/money on sth. 在...上花费时间/金钱 例：I spend two hours on this maths problem.
(2)spend time /money (in) doing sth. 花费时间/金钱做某事 例： They spend two years(in) building this bridge.
(3)spend money for sth .花钱买.... 例：His money was spent for books.
cost的主语是物或某种活动，还可以表示“值”
(1)sth.costs(sb.)+金钱 某物（做某事）花了（某人）多少时间。 例：A new computer costs a lot of money.
(2)(doing) sth costs(sb.) +时间。 某物（做某事）花了（某人）多少时间。 例：Remembering these new words cost him a lot of time.
注：cost的过去式和过去分词都是cost,并且不能用于被动句。
take后常跟双宾语，常见用法：
(1)It takes sb.+sometimes+to do sth. 做某事花了某人多少时间 例：It took them three years to build this road.
(2)doing sth takes sb.+时间， 做某事花了某人多少时间 例：Repairing this car took him the whole afternoon.
pay的基本用法
(1)pay(sb.)money for sth. 付钱（给某人）买...。 例：I have to pay them 20 dollars for this room each month.
(2)pay for sth. 付......的钱。 例：I have to pay for the book lost.
(3)pay for sb. 替某人付钱 例：Don't worry! I'll pay for you.
(4)pay sb. 付钱给某人。 例：They pay us every month.
(5)pay money back 还钱 例：May I borrow 12 yuan from you? I'll pay it back next month.
(6)pay off one's money 还清钱