how能引導定語從句嗎？
答：可以。
特殊疑問詞引導的定語從句
⒈特殊疑問詞"where/when/why/how"也可以引導定語從句。與關係代詞引導定語從句不同，特殊疑問詞引導定語從句時在從句中做狀語，所以特殊疑問詞也叫關係副詞。
This is the city where I met Mary.
He came on Friday,when it was raining very hard.
I don't know the reason why he cried.
That's how/the way he handle the thing.
⒉關係副詞的功能
where 用來修飾表示地方的名詞
when 用來修飾表示時間的'名詞
why 用來修飾 the reason
how 和 the way 只能用其一，表示方式。
⒊where 舉例
This is the place where I lost my key.
I met him at the station ,where there were many passengers.
I bought a desk where I could put my books on.
⒋ when 舉例
That's the year when he graduated.
The son rose at 5:30 ,when most people were still in their dreams.
⒌ why 舉例
I don't know the reason why he cried.
That's the reason why she was late.
⒍ how 舉例
how 只修飾 the way，且只能出現其一
That's how he handle the problem
=That's the way he handle the problem.
I am sick of the way he looks at me.
⒎關係副詞的使用要點
a. 在限定性定語從句中，where不可省略，when 和 why 可以省略，how必須省略。
That's the place he was born.(錯)
That's the place where he was born.(對)
I shall never forget the day (when)
he came (對)
That's the reason (why) he left.(對)
I am sick of the way how he looks at me.(錯)
I am sick of the way he looks at me.(對)
b. 當先行詞做表語時，可省略先行詞。
That's the place where he was born
=That's where he was born
That's the day when he'll come
=That's when he'll come
That's the reason why he left
=That's why he left
That's the way he did it
=That's how he did it
關係定語從句的內容到這裡就可以結束了，對國中同學開始會有點難，希望大家結合課本和資料多多體會，內化為自己的英語能力，文中可能有個別輸入錯誤，希望不會影響理解。
