1、情態(tài)動(dòng)詞 (Modals)。一般和其他動(dòng)詞一起出現(xiàn)。
Can I help you?
Could you help me?
He could not swim across the lake.
May I leave now?
Do you know the way to San Jose?
2、Would
Would you please point the way to ...?
In 2005, I had not know that I would end up going to a top-ranked university.
The man wouldn't help me, even after I had asked.
I'd (would) have called earlier if I'd (had) known you were waiting.
3、Can and Could
My teacher can run a mile in less than 6 minutes.(現(xiàn)在)
When he was younger he could run a mile in less than 6 minutes.（過去）
Could you help me with my grammer assignment?（更禮貌）
You could have called me.(實(shí)際沒發(fā)生)
I could have gone to Harvard if I only studied more diligently.(本可以發(fā)生但實(shí)際上沒發(fā)生)
4、May and Might （Might 并不是過去式）
I might run a marathon.（機(jī)率20%-30%）
Todd may run a marathon.（機(jī)率50%）
Sean may/might have lost his cell phone, so he hasn't been able to call.
Might I have a piece of pie.(更禮貌)
5、Should vs. Must （溫柔 vs 強(qiáng)硬）
If you want better grades, you should study more.
If you want better grades, you must study more.(更嚴(yán)厲)
