diff --git a/advanced-math/exercise/4-integal-of-functions-of-single-variable/integal-of-functions-of-single-variable.pdf b/advanced-math/exercise/4-integal-of-functions-of-single-variable/integal-of-functions-of-single-variable.pdf
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diff --git a/advanced-math/exercise/4-integal-of-functions-of-single-variable/integal-of-functions-of-single-variable.tex b/advanced-math/exercise/4-integal-of-functions-of-single-variable/integal-of-functions-of-single-variable.tex
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--- a/advanced-math/exercise/4-integal-of-functions-of-single-variable/integal-of-functions-of-single-variable.tex
+++ b/advanced-math/exercise/4-integal-of-functions-of-single-variable/integal-of-functions-of-single-variable.tex
@@ -47,6 +47,14 @@
 
 一个函数，可以存在不定积分，而不存在定积分;也可以存在定积分，而不存在不定积分。一个连续函数，一定存在定积分和不定积分;若只有有限个间断点，则定积分存在;若有跳跃间断点，则原函数一定不存在，即不定积分一定不存在。
 
+\subsection{连续性}
+
+\begin{itemize}
+    \item 函数可积，原函数连续。
+    \item 函数连续，原函数可导（连续）。
+    \item 函数有有限个第一类间断点，则原函数连续。
+\end{itemize}
+
 \section{不定积分}
 \subsection{基本积分}