can / could表示本身具备的能力;be able to有某种能力,且设法做成了某事,相当于manage to do sth. 或succeed in doing sth.。另外,be able to不仅用于一般现在时、一般过去时,还可用于一般将来时和完成时等。例如:[文章来自:考试与评价 http://www.trgroup.com.cn/te/ |E2uhueL3j(Y
r] The fire spread through the hotel very quickly but everyone was able to get out. 大火很快蔓延整个旅馆,但所有的人都设法逃了出去。