WHILE
1.He stayed with me while Dad talked with Dr. Smith.
2.I often knit while watching TV.
3.While I have some sympathy for these fellows， I think they went too far.
AND
1. often used to link clauses I came here in 1922 and I have live here ever since.
2. When you are giving advice or a warning， you can use “and” to say what will happen if something is done.
Go by train and you’ll get there quicker.
Do as you’re told and you’ll be all right.
WHERE
1. She was standing exactly where you are standing now.
2.In 1963 we moved to Boston， where my grandparents lived.
3.The treatment will continue until the patient reaches the point where he can walk correctly and safely.
4.You are saying that everyone should be equal， and this is where I disagree.
5.Now， where were we？ Oh yes， we were talking about John.
6.Where others might have been satisfied， Dawson had higher ambitions. （difference） WHICH
（本身無意義，必須接在名詞或代詞后面）
1.定語從句引導詞 Did you see the letter which came today？
Now they were driving by the houses which Andy had described.
2.分割句子，補充說明 The house，which was completed in 1856， was famous for its huge marble staircase.
He was educated at the local grammar school， after which he went on to Cambridge.
She may have missed the train， in which case she won’t arrive for another hour.
THAT 多用于同位語從句和－thing的定語從句中。
WHAT
（有實際意義，可用于賓語從句和主語從句）
1. No one knows exactly what happened.
2.It is not clear to what extent these views were shared.
3.I could get you a job here if that’s what you want.
4. What that kid needs is some love and affection.
5. What matters is the British people and British jobs.
AS
1.比較
His last album sold half a million copies and we hope this one will be just as popular./ They want peace as much as we do.
2.作為，正如… We’d better leave things as they are until the police arrive.
David， as you know， has not been well lately.
3.看作，看待
The result of last week’s election will be seen as a victory.
4.當…時候= while or when
I saw Peter as I was getting off the bus.
5.原因 As it was getting late， I turned around to start for home.
6.讓步= though Try as she might， Sue couldn’t get the door open.
The bag has narrow straps， so it may be worn over the shoulder or carried in the hand.
I’d be in trouble if I let on. So I kept mum.
When the meal was finished， Rachel washed up and made coffee.
I would have liked to have learnt French， but I was denied （=not given） the opportunity.
The opportunity was denied （to） me at school.
The prestige is denied （to） the classroom teacher.
The classroom teacher is denied the prestige.