diff --git a/docs/计算机网络/topdown.en.md b/docs/计算机网络/topdown.en.md
index 5b3fac7e..64344b0a 100644
--- a/docs/计算机网络/topdown.en.md
+++ b/docs/计算机网络/topdown.en.md
@@ -6,9 +6,9 @@
 - Prerequisites: basic knowledge about computer system
 - Programming Lanuages: None
 - Difficulty: 🌟🌟🌟
-- Class Hour: hours
+- Class Hour: 40 hours
 
-*Computer Networking: A Top-Down Approach* is a classic textbook in the field of computer networking. The two authors, Jim Kurose and Keith Ross, have carefully crafted a course website supporting the textbook, recorded online course videos, interactive online chapter tests and labs for packet analysis using WireShark. The only pity is that this course doesn't have hardcore programming assignments, and Stanford's [CS144](./CS144.en.md) makes up for that.
+*Computer Networking: A Top-Down Approach* is a classic textbook in the field of computer networking. The two authors, Jim Kurose and Keith Ross, have carefully crafted a course website to support the textbook, with lecture recordings, interactive online questions, and WireShark labs for network packet analysis. The only pity is that this course doesn't have hardcore programming assignments, and Stanford's [CS144](./CS144.en.md) makes up for that.
 
 ## Course Resources