diff --git a/SICP/slide03.tm b/SICP/slide03.tm
index 29db6da..e5aceb6 100644
--- a/SICP/slide03.tm
+++ b/SICP/slide03.tm
@@ -57,7 +57,87 @@
         Tree Recursion
       </cell>>>>
     </wide-tabular>
-  </shown>>
+  </shown>|<\hidden>
+    <tit|\<#6761\>\<#4EF6\>\<#8868\>\<#8FBE\>\<#5F0F\>\<#548C\>\<#8C13\>\<#8BCD\>\V\<#77ED\>\<#8DEF\>\<#8FD0\>\<#7B97\>>
+
+    <\itemize>
+      <item>\<#5E94\>\<#7528\>\<#5E8F\>\<#6C42\>\<#503C\>\<#FF08\>Scheme\<#4F7F\>\<#7528\>\<#7684\>\<#662F\>\<#5E94\>\<#7528\>\<#5E8F\>\<#6C42\>\<#503C\>\<#FF09\>
+
+      <item>\<#6B63\>\<#5219\>\<#5E8F\>\<#6C42\>\<#503C\>
+    </itemize>
+
+    <subparagraph|\<#6848\>\<#4F8B\>\<#5206\>\<#6790\>\<#FF1A\>\<#5B9E\>\<#73B0\>\<#6C42\>\<#7EDD\>\<#5BF9\>\<#503C\>\<#7684\>\<#591A\>\<#79CD\>\<#65B9\>\<#5F0F\>>
+
+    <\with|par-columns|2>
+      <\equation*>
+        <around|\||x|\|>=<around*|{|<tabular|<tformat|<cwith|1|-1|1|1|cell-halign|r>|<cwith|1|-1|2|2|cell-halign|l>|<cwith|1|-1|3|3|cell-halign|l>|<table|<row|<cell|x>|<cell|<with|mode|text|if>>|<cell|x\<gtr\>0,>>|<row|<cell|0>|<cell|<with|mode|text|if>>|<cell|x=0,>>|<row|<cell|-x>|<cell|<with|mode|text|if>>|<cell|x\<less\>0.>>>>>|\<nobracket\>>
+      </equation*>
+
+      <\session|scheme|default>
+        <\unfolded-io|Scheme] >
+          (define (abs1 x)
+
+          \ \ (cond ((\<gtr\> x 0) x)
+
+          \ \ \ \ \ \ \ \ ((= x 0) 0)
+
+          \ \ \ \ \ \ \ \ (else (- x))))
+        <|unfolded-io>
+          abs1
+        </unfolded-io>
+
+        <\unfolded-io|Scheme] >
+          (define (abs2 x)
+
+          \ \ (if (\<gtr\> x 0)
+
+          \ \ \ \ \ \ x
+
+          \ \ \ \ \ \ (- x)))
+        <|unfolded-io>
+          abs2
+        </unfolded-io>
+
+        <\unfolded-io|Scheme] >
+          (define (abs3 x)
+
+          \ \ (or (and (\<gtr\> x) x) (- x)))
+        <|unfolded-io>
+          abs3
+        </unfolded-io>
+
+        <\unfolded-io|Scheme] >
+          (abs1 1)
+        <|unfolded-io>
+          1
+        </unfolded-io>
+
+        <\unfolded-io|Scheme] >
+          (abs1 -1)
+        <|unfolded-io>
+          1
+        </unfolded-io>
+
+        <\input|Scheme] >
+          \;
+        </input>
+      </session>
+    </with>
+
+    <\folded>
+      <\question>
+        \<#4E3A\>\<#4EC0\>\<#4E48\><scm|if>\<#548C\><scm|cond>\<#662F\>\<#5FC5\>\<#987B\>\<#7684\>\<#FF1F\>
+      </question>
+    <|folded>
+      <\exercise>
+        \<#4F7F\>\<#7528\><scm|if>\<#5B9E\>\<#73B0\><scm|and>\<#548C\><scm|or>\<#3002\>
+      </exercise>
+
+      \<#53C2\>\<#8003\>\<#6587\>\<#6863\>\<#FF1A\><slink|https://www.scheme.com/tspl2d/grammar.html>
+    </folded>
+
+    \;
+  </hidden>>
 </body>
 
 <\initial>
@@ -66,70 +146,13 @@
     <associate|marked-color|pastel yellow>
     <associate|page-medium|beamer>
     <associate|page-screen-margin|false>
+    <associate|par-columns|1>
     <associate|preamble|false>
   </collection>
 </initial>
 
 <\references>
   <\collection>
-    <associate|auto-1|<tuple|?|?|slide01.tm>>
-    <associate|auto-10|<tuple|2|?|slide01.tm>>
-    <associate|auto-11|<tuple|1|?|slide01.tm>>
-    <associate|auto-12|<tuple|applicative order evaluation|?|slide01.tm>>
-    <associate|auto-13|<tuple|2|?|slide01.tm>>
-    <associate|auto-14|<tuple|normal order evaluation|?|slide01.tm>>
-    <associate|auto-15|<tuple|2|?|slide01.tm>>
-    <associate|auto-2|<tuple|normal order evaluation|?|slide01.tm>>
-    <associate|auto-3|<tuple|2|?|slide01.tm>>
-    <associate|auto-4|<tuple|2|?|slide01.tm>>
-    <associate|auto-5|<tuple|normal order evaluation|?|slide01.tm>>
-    <associate|auto-6|<tuple|2|?|slide01.tm>>
-    <associate|auto-7|<tuple|2|?|slide01.tm>>
-    <associate|auto-8|<tuple|2|?|slide01.tm>>
-    <associate|auto-9|<tuple|normal order evaluation|?|slide01.tm>>
+    <associate|auto-1|<tuple|1|?>>
   </collection>
-</references>
-
-<\auxiliary>
-  <\collection>
-    <\associate|figure>
-      <tuple|normal|<surround|<hidden-binding|<tuple>|1>||\<#64CD\>\<#4F5C\>\<#7B26\>\<#548C\>\<#64CD\>\<#4F5C\>\<#6570\>>|<pageref|auto-7>>
-
-      <tuple|normal|<surround|<hidden-binding|<tuple>|2>||\<#4E00\>\<#4E2A\>\<#5177\>\<#4F53\>\<#7684\>\<#4F8B\>\<#5B50\>>|<pageref|auto-8>>
-    </associate>
-    <\associate|gly>
-      <tuple|normal|primitive|\<#539F\>\<#8BED\>|<pageref|auto-1>>
-
-      <tuple|normal|expression|\<#8868\>\<#8FBE\>\<#5F0F\>|<pageref|auto-2>>
-
-      <tuple|normal|procedure|\<#51FD\>\<#6570\>|<pageref|auto-3>>
-
-      <tuple|normal|combination|\<#7EC4\>\<#5408\>|<pageref|auto-4>>
-
-      <tuple|normal|abstraction|\<#62BD\>\<#8C61\>|<pageref|auto-5>>
-
-      <tuple|normal|combinations|\<#7EC4\>\<#5408\>\<#5F0F\>|<pageref|auto-6>>
-
-      <tuple|normal|compound procedure|\<#590D\>\<#5408\>\<#51FD\>\<#6570\>|<pageref|auto-9>>
-
-      <tuple|normal|substitution model|\<#4EE3\>\<#6362\>\<#6A21\>\<#578B\>|<pageref|auto-10>>
-
-      <tuple|normal|applicative order evaluation|\<#5E94\>\<#7528\>\<#5E8F\>\<#6C42\>\<#503C\>|<pageref|auto-12>>
-
-      <tuple|normal|normal order evaluation|\<#6B63\>\<#5219\>\<#5E8F\>\<#6C42\>\<#503C\>|<pageref|auto-14>>
-    </associate>
-    <\associate|toc>
-      <with|par-left|<quote|3tab>|\<#5E94\>\<#7528\>\<#5E8F\>\<#6C42\>\<#503C\>
-      <datoms|<macro|x|<repeat|<arg|x>|<with|font-series|medium|<with|font-size|1|<space|0.2fn>.<space|0.2fn>>>>>|<htab|5mm>>
-      <no-break><pageref|auto-11>>
-
-      <with|par-left|<quote|3tab>|\<#6B63\>\<#5219\>\<#5E8F\>\<#6C42\>\<#503C\>
-      <datoms|<macro|x|<repeat|<arg|x>|<with|font-series|medium|<with|font-size|1|<space|0.2fn>.<space|0.2fn>>>>>|<htab|5mm>>
-      <no-break><pageref|auto-13>>
-
-      <vspace*|1fn><with|font-series|<quote|bold>|math-font-series|<quote|bold>|\<#672F\>\<#8BED\>\<#8868\>>
-      <datoms|<macro|x|<repeat|<arg|x>|<with|font-series|medium|<with|font-size|1|<space|0.2fn>.<space|0.2fn>>>>>|<htab|5mm>>
-      <no-break><pageref|auto-15><vspace|0.5fn>
-    </associate>
-  </collection>
-</auxiliary>
\ No newline at end of file
+</references>
\ No newline at end of file