could 和 be able to 问题

来源：百度知道 编辑：UC知道 时间：2024/05/30 11:32:57
It could only get over the mountains if it rose to 10000 feet.
This means it _________ over the mountains.
A.would succeed in getting
B.got
C.was able to get
D.had got

应选哪个？请说明原因。
为什么不选C？

答案是 A.would succeed in getting 。虚拟语气。
虚拟条件句的主句中不能缺少would,should,might或could。
was able to get改为would be able to get也可以。

对楼上的答案表赞同,同时再进行补充:
be able to通常只用于人,表示"某人有能力做什么",如果主语不是人的话则极少用这种表达方式.正如这句话,主语是it,通常不会选择be able to.
can也表示具备某种能力,使用的范围比be able to要广泛得多.若问及二者的区别,那就是be able to所表达的能力多指后天习得的,而can多指与生俱来的.
例如:
He is able to tackle problems himself now.
He can sing well when he was only three.

因个人能力而能够做什么

我赞同楼上答案，见解很好，我也长见识了。