diff --git a/assets/section_3.1_1686980736370_0.edn b/assets/section_3.1_1686980736370_0.edn
index 3251692..8a89548 100644
--- a/assets/section_3.1_1686980736370_0.edn
+++ b/assets/section_3.1_1686980736370_0.edn
@@ -122,5 +122,17 @@
                           :rects (),
                           :page 26},
                :content {:text "[:span]", :image 1686983261351},
+               :properties {:color "yellow"}}
+              {:id #uuid "648d5392-d808-41be-82da-e23934db4f9f",
+               :page 27,
+               :position {:bounding {:x1 45,
+                                     :y1 82.416015625,
+                                     :x2 629,
+                                     :y2 463.416015625,
+                                     :width 677.2919999999999,
+                                     :height 507.96853333333326},
+                          :rects (),
+                          :page 27},
+               :content {:text "[:span]", :image 1686983569626},
                :properties {:color "yellow"}}],
  :extra {:page 27}}
diff --git a/assets/section_3.1_1686980736370_0/27_648d5392-d808-41be-82da-e23934db4f9f_1686983569626.png b/assets/section_3.1_1686980736370_0/27_648d5392-d808-41be-82da-e23934db4f9f_1686983569626.png
new file mode 100644
index 0000000..5c8200d
Binary files /dev/null and b/assets/section_3.1_1686980736370_0/27_648d5392-d808-41be-82da-e23934db4f9f_1686983569626.png differ
diff --git a/pages/hls__section_3.1_1686980736370_0.md b/pages/hls__section_3.1_1686980736370_0.md
index 2ed9915..a8677cf 100644
--- a/pages/hls__section_3.1_1686980736370_0.md
+++ b/pages/hls__section_3.1_1686980736370_0.md
@@ -68,4 +68,11 @@ file-path:: ../assets/section_3.1_1686980736370_0.pdf
   hl-color:: yellow
   id:: 648d525e-f08f-4838-9103-0218fb369579
   hl-type:: area
-  hl-stamp:: 1686983261351
\ No newline at end of file
+  hl-stamp:: 1686983261351
+- [:span]
+  ls-type:: annotation
+  hl-page:: 27
+  hl-color:: yellow
+  id:: 648d5392-d808-41be-82da-e23934db4f9f
+  hl-type:: area
+  hl-stamp:: 1686983569626
\ No newline at end of file
diff --git a/pages/总复习2023t1.md b/pages/总复习2023t1.md
index 369f1db..c892400 100644
--- a/pages/总复习2023t1.md
+++ b/pages/总复习2023t1.md
@@ -2892,7 +2892,9 @@
 						- Continuous random vector
 							- Definition of jpdf:
 								- ((648d525e-f08f-4838-9103-0218fb369579))
-							-
+							- Calculating pdf and d.f
+								- ((648d5392-d808-41be-82da-e23934db4f9f))
+								-
 			- LATER 学积分
 			  :LOGBOOK:
 			  CLOCK: [2023-06-03 Sat 17:05:07]--[2023-06-03 Sat 17:05:08] =>  00:00:01