1.be able to 后接动词原形,表示某人有做某事的能力,与can的用法相近。如:
I am able to speak English.我能讲英语。
2.be able to 与can的辨析:
①be able to有多种时态,如: was/were able to,will/ shall be able to,have/has been able to等,而can只有两种时态,即can和could。
②be able to 强调通过努力而获得的能力,而can则强调自身已具有的能力。如:
She can sing the song in English.
她能用英语唱这首歌。
He will be able to sing this song in English in a few hours,too.
几小时之后,他也能用英语唱这首歌。
