diff --git a/Main.hs b/Main.hs
--- a/Main.hs
+++ b/Main.hs
@@ -307,7 +307,7 @@
     Content "We can define a function. Let's define a function and test it."
      ["(define $f (lambda [$x] (+ x 1)))", "(f 10)", "(define $g (lambda [$x $y] (* x y)))", "(g 10 20)", "(define $sum (lambda [$n] (foldl + 0 (take n nats))))", "(sum 10)"]
      ["Try to define a 'fact' function."],
-    Content "We can compare numbers using functions that return '#t' or '#f'.\n'#t' means the true.\n#f means the false.\nFunctions that return '#t' or '#f' are called \"predicates\"."
+    Content "We can compare numbers using functions that return '#t' or '#f'.\n'#t' means the true.\n'#f' means the false.\nFunctions that return '#t' or '#f' are called \"predicates\"."
      ["(eq? 1 1)", "(gt? 1 1)", "(lt? 1 1)",  "(gte? 1 1)", "(lte? 1 1)"]
      [],
     Content "With the 'while' function, we can extract all head elements that satisfy the predicate.\n'primes' is a infinites list that contains all prime numbers."
@@ -326,7 +326,7 @@
      ["[1]", "[[[1]]]"]
      [],
     Content "With the 'zip' function, we can combine two lists as follow."
-     ["(take 100 (zip * nats nats))", "(take 100 (zip * primes primes))"]
+     ["(take 100 (zip nats nats))", "(take 100 (zip primes primes))"]
      ["Try to create the prime table that is like '{[1 2] [2 3] [3 5] [4 7] [5 11] ...}'"],
     Content "We can bind a value to a variable with a 'define' expression.\nWe can easily get the value we bound to the variable."
      ["(define $x 10)", "x", "(define $ps (zip nats primes))", "(take 100 ps)"]
diff --git a/egison-tutorial.cabal b/egison-tutorial.cabal
--- a/egison-tutorial.cabal
+++ b/egison-tutorial.cabal
@@ -1,8 +1,8 @@
 Name:                egison-tutorial
-Version:             3.3.4
+Version:             3.3.5
 Synopsis:            A tutorial program for the programming language Egison
 Description:         A tutorial program for the programming language Egison.
-                     Egison is the programming langugage that realized non-linear pattern-matching with unfree data types.
+                     Egison is the programming langugage that realized non-linear pattern-matching against unfree data types.
                      With Egison, you can represent pattern-matching with unfree data types intuitively, especially for collection data, such as lists, multisets, sets.
                      Please learn Egison with this tutorial program!
 Homepage:            http://www.egison.org
@@ -20,4 +20,4 @@
 
 Executable egison-tutorial
   Main-is:             Main.hs
-  Build-depends:       egison >= 3.3.4, base >= 4.0 && < 5, array, containers, unordered-containers, haskeline, transformers, mtl, parsec >= 3.0, directory, ghc, ghc-paths, filepath, regex-posix, strict-io, bytestring
+  Build-depends:       egison >= 3.3.7, base >= 4.0 && < 5, array, containers, unordered-containers, haskeline, transformers, mtl, parsec >= 3.0, directory, ghc, ghc-paths, filepath, regex-posix, strict-io, bytestring