在高中英语学习中，定语从句是一个重要的语法知识点。为了帮助大家更好地掌握这一内容，以下提供了一些专项练习题，并附有详细的答案解析。
练习题
1. The boy _______ you talked to just now is my cousin.
A. who B. whom C. whose D. which
2. The book _______ I borrowed from the library is very interesting.
A. that B. what C. where D. when
3. This is the factory _______ we visited last week.
A. where B. which C. who D. whose
4. Do you know the girl _______ is standing under the tree?
A. who B. whom C. whose D. which
5. He is the man _______ gave us a talk yesterday.
A. who B. whom C. whose D. which
答案及解析
1. 答案：B
解析：此句中“you talked to”是定语从句，修饰先行词“the boy”，关系代词在从句中作宾语，因此选择“whom”。
2. 答案：A
解析：“I borrowed from the library”是定语从句，修饰先行词“the book”，关系代词在从句中作宾语，可以用“that”或“which”，但习惯上常用“that”。
3. 答案：B
解析：“we visited last week”是定语从句，修饰先行词“the factory”，关系代词在从句中作宾语，因此选择“which”。
4. 答案：A
解析：“is standing under the tree”是定语从句，修饰先行词“the girl”，关系代词在从句中作主语，因此选择“who”。
5. 答案：A
解析：“gave us a talk yesterday”是定语从句，修饰先行词“the man”，关系代词在从句中作主语，因此选择“who”。
通过以上练习题和解析，希望大家能够更加熟练地运用定语从句。继续努力，相信你的英语水平会不断提高！
