請問That/It is the first time (that) I have read the book.這句話爲

題目：

請問That/It is the first time (that) I have read the book.這句話爲什麼不是主語從句
如何判定這樣的句子是主語從句還是定語從句?

解答：

這個句子後面的(that) I have read the book.修辭的是the first time爲定語,所以爲定語從句
主要是看句子修辭的那個先行詞代表句子的哪個部分,修辭的是主語部分,就是主語從句,修辭的是定語部分,就是定語從句.
再問： 要是能舉個例子就更好了 謝謝
再答： That he finished writing the composition in such a short time surprised us all. That he finished writing the composition in such a short time 這前半部分就是主語從句，因爲整個句子可以看做是「That he finished writing the composition in such a short time」(主語） "surprised"（謂語） "us all"（賓語） 所以前面這段就是「that"引導的主語從句 給你幾個主語從句的例子： Whether we will go for an outing tomorrow remains unknown. Who will be our monitor hasn't been decided yet. Whom we must study for is a question of great importance. What caused the accident remains unknown. Who the watch belongs to is unknown. He is the man （whom/that） I saw yesterday.這裡的（whom/that） I saw yesterday.就是定語從句，起到限定修飾」the man"的作用 給你幾個定語從句的例子： The man whom you spoke to just now is our English teacher. The prosperity which/that had never appeared before took on in the countryside. A child whose parents are dead is called an orphan He lives in a room whose window faces south. By the time when you arrived in London, we had stayed there for two weeks.