這題英文關代為什選D呢?

文法/句法未必能"解釋詳盡"正確答案的理由，不如改變一個方法理解"其他答案"如何作出句子來，便可能學會多種寫法，而不單只會一個答案：

先說D這個"正確"答案的句法：
In the library, you can read books which interest you.
which是修飾或加強前文名詞(books)的意義，which後若沒另一個主詞便當作主詞是前字"books"，因此interest動詞表達"這些書"是「令你"有興趣"的」。

若which這連接詞不變，其他的答案要如何修改才可以"成立"：
A) In the library, you can read books which you are interested.
which後主詞改變了由you開始，是另一子句，因此便要寫成"完整句"S+v+obj/adj.

B) In the library, you can read books which interest(s) you.
這答案的動詞+s錯了配對名詞(books)，因此錯的。日常會在見工面試時被問：
What Interests You About This Position? 

C) interest in的東西是你參與的事情(由工作/職位至消閒活動或嗜好，但甚少用於看書(reading)。若用於原句，interest in的便不是books而是reading這行為/活動。因此難以把原句改寫。

In the library you can read books
(A)you interest---------which=relative pronoun( as you mentioned), about 1st part of subject you/or books--->S+be+interested--eg:-interested (adj) in my book-reading, or my interested bk-reading. Also no two subjects in a sentence-------------(x)
(B)interests you----------when the subject books is plural, the verb should be plural=interest with no "s" added----------------(x)
(C)you interest in----should be changed to "S+be+interested in"--------------------------(x)
(D) interest you------the subject books is plural needs a plural verb=interest; not interest"s"; meaning make you feel interest;=which interested you ie:-interested(adj) in your book-reading; Or your interested(adj) book-reading.------------------------(o)

D.interest you

interest是動詞 中文叫「引起興建」


In the library,you can read books which interest you.

在圖書館中 你可以讀那些你有興趣的書


A.you interest

文法不太通

建議改成 you are interested in


B. interests you

文法不太通

要改成 interest  you

因為 interest 的實際主詞是books-->複數 動詞不用+s


C.you interest in

文法不太通

建議改成 you are interested in

有興趣  人+be+interested in