be able to : 能够做,可以做
manage to 是做了但是费了很大的力,或者尽量往做.
只用be able to
a. 位于助动词后。
b. 情态动词后。
c. 表达过往某时刻动做时。
d. 用于句首表达前提。
e. 表达胜利地做了某事时，只能用was/were able to， 不克不及用could。
He was able to flee Europe before the war broke out.
= He managed to flee Europe before the war broke out.
. manage 一般用法： manage to do; manage it
特殊重视： manage to do表达胜利地做成某事，不胜利不成以用
0