diff --git a/sections/3C.typ b/sections/3C.typ
new file mode 100644
index 0000000..e69de29
diff --git a/toc.typ b/toc.typ
index 136dda2..d7b02ec 100644
--- a/toc.typ
+++ b/toc.typ
@@ -6,5 +6,5 @@
 	sections: ([张成空间和线性无关性], [基], [维数]),
 ), (
 	title: [线性映射],
-	sections: ([线性映射的向量空间], [零空间和值域],),
+	sections: ([线性映射的向量空间], [零空间和值域], [矩阵],),
 ))