—Where are the books?— in the bookcase. Do you need now?A. It’s; it B. They’re; they C. T

问题补充：

—Where are the books?

— in the bookcase. Do you need now?

A. It’s; it

B. They’re; they

C. They’re; them

D. It’s; them

答案：

A. It’s; it

B. They’re; they

(答案→)C. They’re; them

D. It’s; them

解析：it它；they人称代词主格，他们；them人称代词宾格，他们。句意：书在哪儿？——他们在书架上。你需要他们吗？结合语境可知下文前一空指的是上文提到的复数名词，做主语，故用主格人称代词they，下文代词指代前文提到的they，作宾语，故用宾格形式，选C。