diff --git a/assets/section_2.3_1686916498071_0.edn b/assets/section_2.3_1686916498071_0.edn
index 3eef5c1..8e29fc6 100644
--- a/assets/section_2.3_1686916498071_0.edn
+++ b/assets/section_2.3_1686916498071_0.edn
@@ -21,5 +21,17 @@
                           :rects (),
                           :page 16},
                :content {:text "[:span]", :image 1686917782356},
+               :properties {:color "yellow"}}
+              {:id #uuid "648c52d9-ea03-4835-8080-52ba5e6c3122",
+               :page 16,
+               :position {:bounding {:x1 48.16666603088379,
+                                     :y1 315.74951171875,
+                                     :x2 659.1666660308838,
+                                     :y2 528.74951171875,
+                                     :width 725.67,
+                                     :height 544.252},
+                          :rects (),
+                          :page 16},
+               :content {:text "[:span]", :image 1686917848708},
                :properties {:color "yellow"}}],
- :extra {:page 16}}
+ :extra {:page 17}}
diff --git a/assets/section_2.3_1686916498071_0/16_648c52d9-ea03-4835-8080-52ba5e6c3122_1686917848708.png b/assets/section_2.3_1686916498071_0/16_648c52d9-ea03-4835-8080-52ba5e6c3122_1686917848708.png
new file mode 100644
index 0000000..bfd247d
Binary files /dev/null and b/assets/section_2.3_1686916498071_0/16_648c52d9-ea03-4835-8080-52ba5e6c3122_1686917848708.png differ
diff --git a/pages/hls__section_2.3_1686916498071_0.md b/pages/hls__section_2.3_1686916498071_0.md
index 51eea4d..80e1b70 100644
--- a/pages/hls__section_2.3_1686916498071_0.md
+++ b/pages/hls__section_2.3_1686916498071_0.md
@@ -14,4 +14,11 @@ file-path:: ../assets/section_2.3_1686916498071_0.pdf
   hl-color:: yellow
   id:: 648c5298-fb84-4e9c-b816-7df1a7ad9a66
   hl-type:: area
-  hl-stamp:: 1686917782356
\ No newline at end of file
+  hl-stamp:: 1686917782356
+- [:span]
+  ls-type:: annotation
+  hl-page:: 16
+  hl-color:: yellow
+  id:: 648c52d9-ea03-4835-8080-52ba5e6c3122
+  hl-type:: area
+  hl-stamp:: 1686917848708
\ No newline at end of file
diff --git a/pages/总复习2023t1.md b/pages/总复习2023t1.md
index a71dd1f..b598ef7 100644
--- a/pages/总复习2023t1.md
+++ b/pages/总复习2023t1.md
@@ -2720,8 +2720,11 @@
 							- ((648c48ac-76be-4848-af0d-1532467c8d68))
 					- Mathematical Expectation and Variance ![section 2.3.pdf](../assets/section_2.3_1686916498071_0.pdf)
 						- Expectation
-							- ((648c4e9e-5515-4da3-bc6b-39d6969f5f14))
-								- Example
+							- Definitions :-> ((648c4e9e-5515-4da3-bc6b-39d6969f5f14))
+								- Examples:
+									- ((648c5298-fb84-4e9c-b816-7df1a7ad9a66)) #flashcard
+										- ((648c52d9-ea03-4835-8080-52ba5e6c3122))
+									-
 			- LATER 学积分
 			  :LOGBOOK:
 			  CLOCK: [2023-06-03 Sat 17:05:07]--[2023-06-03 Sat 17:05:08] =>  00:00:01