6、者在某个客观的场合和背景下,能做到的事情。Ican’tswim,butIamsureIwillbeabletoswimthroughmorepracticing.表示特定的某一过去能力或表示成功地做了某事时,只能用was/were able to, 不能用could。He _________ flee Europe before the war broke out.Note:wasabletoAbigfirebrokeoutinABChotelyesterday.Luckily,everyone______