Id like to,but i cant -the time because im taking an exam to

选Dspend 的主语只能是人,不能使物。句子结构是：人+ spend + 钱/ 时间 + on + 物。He spent $ 300 on this bike。He spent 3 hours on his homework。或者,人+ spend + 钱/ 时间 + in + doing + 物。He spent $ 300 in buying the bike。He spent 3 hours in doing his homework。cost主语只能是物,不能使人。意思是消费钱财。The bike cost him $300。afford意思是‘花得起或花不起金钱和时间’。I can't afford the bike。I can't afford to buy a bike。pay 支付的意思。(自己分析下面句子的用法区别)He paid $ 300。He paid $ 300 for the bike。He paid $300 to the seller for the bike。take 的主语只能事物,不能使人。通常用it作主语。It will take me 3 hours to do my homework。It took me 30 minutes to walk from here to my school。