diff --git a/assets/section_2.5_1686968005870_0.edn b/assets/section_2.5_1686968005870_0.edn
index 97c0767..23bb010 100644
--- a/assets/section_2.5_1686968005870_0.edn
+++ b/assets/section_2.5_1686968005870_0.edn
@@ -165,5 +165,17 @@
                           :rects (),
                           :page 37},
                :content {:text "[:span]", :image 1686973492094},
+               :properties {:color "yellow"}}
+              {:id #uuid "648d2cfd-2cef-48d2-b791-e5ac01e43fd8",
+               :page 39,
+               :position {:bounding {:x1 45,
+                                     :y1 237.08203125,
+                                     :x2 644,
+                                     :y2 422.08203125,
+                                     :width 677.2919999999999,
+                                     :height 507.96853333333326},
+                          :rects (),
+                          :page 39},
+               :content {:text "[:span]", :image 1686973691894},
                :properties {:color "yellow"}}],
  :extra {:page 39}}
diff --git a/assets/section_2.5_1686968005870_0/39_648d2cfd-2cef-48d2-b791-e5ac01e43fd8_1686973691894.png b/assets/section_2.5_1686968005870_0/39_648d2cfd-2cef-48d2-b791-e5ac01e43fd8_1686973691894.png
new file mode 100644
index 0000000..2b3e011
Binary files /dev/null and b/assets/section_2.5_1686968005870_0/39_648d2cfd-2cef-48d2-b791-e5ac01e43fd8_1686973691894.png differ
diff --git a/pages/hls__section_2.5_1686968005870_0.md b/pages/hls__section_2.5_1686968005870_0.md
index 5ec258f..a19104b 100644
--- a/pages/hls__section_2.5_1686968005870_0.md
+++ b/pages/hls__section_2.5_1686968005870_0.md
@@ -98,4 +98,11 @@ file-path:: ../assets/section_2.5_1686968005870_0.pdf
   hl-color:: yellow
   id:: 648d2c35-041a-4575-b39d-c42c1a6f532f
   hl-type:: area
-  hl-stamp:: 1686973492094
\ No newline at end of file
+  hl-stamp:: 1686973492094
+- [:span]
+  ls-type:: annotation
+  hl-page:: 39
+  hl-color:: yellow
+  id:: 648d2cfd-2cef-48d2-b791-e5ac01e43fd8
+  hl-type:: area
+  hl-stamp:: 1686973691894
\ No newline at end of file
diff --git a/pages/总复习2023t1.md b/pages/总复习2023t1.md
index c2bc321..64502d8 100644
--- a/pages/总复习2023t1.md
+++ b/pages/总复习2023t1.md
@@ -2830,8 +2830,8 @@
 								  id:: 648d29b8-bd11-4eb6-9240-941c2ff636f1
 								- Calculating negative ones :-> ((648d29da-0535-4dd3-ae79-48b34e047339))
 								- Example
-									- in specified  ((648d2c35-041a-4575-b39d-c42c1a6f532f))
-									-
+									- in specified interval ((648d2c35-041a-4575-b39d-c42c1a6f532f))
+									- without knowing $$\mu$$ and $$\sigma$$: ((648d2cfd-2cef-48d2-b791-e5ac01e43fd8))
 				-
 				-
 			- LATER 学积分