這個句子后面的(that) I have read the book.修辭的是the first time為定語,所以為定語從句
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.要是能舉個例子就更好了 謝謝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，因為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(dǎo)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.這里的（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 orphanHe lives in a room whose window faces south.By the time when you arrived in London, we had stayed there for two weeks.