偶认为把can 和be able to一起考时，前者指的是可以做某事，后者倾向于说有能力做某事
ability to do sth & capability of doing sth指的都是能力，偶看到他们第一步的判断方式是看后面的介词对不对，然后再结合其它语法点，语序等等，一般都能搞定。至于具体意思区别，权威的语法书也很模糊：
“ability is a person's mental or physical power to do sth. Capability is the general power or ability of a machine or organization to do sth or be used to do sth. Capability also can be applied to people, but ability is usually the simpler choice" | 
