would与usedto都可用来表示过去经常性或习惯性的动作,常常可以换用。如:(1)Whenwewereboysweusedto／wouldgoswimmingeverysummer.小时候,每到夏天我们都要去游泳。(2)Heusedto／wouldspendeverypennyheearnedonbooks.过去,他通常把挣来的钱全花在买书上。would与usedto都不能用来表示动作发生的具体频度或具体的一段时间。例如,不能说: Both would and used to be used to represent past or customary actions in the past and can often be used interchangeably. Such as: (1)Whenwewereboysweusedto/wouldgoswimmingeverysummer. As a child, we must go swimming every summer. (2) Heusedto/wouldspendeverypennyheearnedonbooks. In the past, he usually spent all his money on books. Neither would nor usedto can be used to indicate the specific frequency of action or the specific period of time. For example, can’t say: