diff --git a/src/main/java/com/toc/COMMENT-SYSTEM.md b/src/main/java/com/toc/COMMENT-SYSTEM.md
new file mode 100644
index 0000000..a95fdf0
--- /dev/null
+++ b/src/main/java/com/toc/COMMENT-SYSTEM.md
@@ -0,0 +1,6 @@
+**Index**
+
+评论系统设计
+# 评论系统设计[Top]
+
+[如何设计评论系统](https://zhuanlan.zhihu.com/p/455199524)
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diff --git a/src/main/java/com/toc/NCOV-SYSTEM.md b/src/main/java/com/toc/NCOV-SYSTEM.md
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+**Index**
+
+核酸系统
+# 核酸系统[Top]
+[假如我是核酸系统架构师](https://mp.weixin.qq.com/s/s2Q0qVYzB6oIz2VoVmnR8A)
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