（外研版）初中英语七年级下册知识点归纳总结(11)

eg：
He may be a middle school student. 他可能是个中学生。
She may be watching TV now. 现在她也许在看电视。
二、短语
1. be sure 确信, 一定，后面可跟不定式或从句。
eg：
I am sure to go to Beijing tomorrow. = I am sure that I will go to Beijing tomorrow.我明天一定会去北京。
He is sure to visit the Great Wall next week. = He is sure that he will visit the Great Wall next week. 他下周一定会去参观长城。
2. be able to …能够做…
be able to 与can用法与区别:
①be 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。
eg：
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 minutes, too.
几小时之后，他也能用英语唱这首歌。
②be able to 强调一种结果，而can只强调一种可能。
eg：
Luckily, he was able to escape from the big fire in the end. 幸运的是，他终于逃出了大火。
If he got here a few hours earlier, I could save him. 要是他早几小时来，我还能救他。
③be able to 可以有各种时态；而can只有一般现在和一般过去两种时态。
eg：
I could help you last night, but you didn’t come. 昨天晚上我能帮你，而你又没来。
Can you see it there? 你能看见它在那儿吗？
He is / was / will be able to help you. 他能帮你的忙.