有一读者问： 如何理解下面一句话：
(1)Six persons were able to swim to land but two others are still missing.
这句话的意思是：六个人已经奋力游上了（海）岸，但还有两个人下落不明。你的困难大概在于这里为什么用were able to swim 而不用swam 或managed to swim。你如果查一下一部好的英语词典，比如说《朗文当代英语词典》（Longman Dictionary of Contemporary English），即可查到（如在上述词典的could项下）be able to 有时就相当于manage to, 二者都意谓“努力而且成功 （try then succeed）”。这样，你就会理解为什么 were able to swim 的意思是“努力游到”了。be able to 作如此解的情况并不罕见，再如：
(2)I am glad we were able to get the tickets.
(3)In the end they were able to rescue the cat on the roof.
(4)Luckily he was able to escape without injury.
(5)The airplane was damaged but the pilot was able to bring it safely to land.
