diff --git a/nemubot/tools/human.py b/nemubot/tools/human.py
index b751409..588ac1f 100644
--- a/nemubot/tools/human.py
+++ b/nemubot/tools/human.py
@@ -57,3 +57,13 @@ def word_distance(str1, str2):
                 )
 
     return d[len(str1)][len(str2)]
+
+
+def guess(pattern, expect):
+    if len(expect):
+        se = sorted([(e, word_distance(pattern, e)) for e in expect], key=lambda x: x[1])
+        _, m = se[0]
+        for e, wd in se:
+            if wd > m or wd > 1 + len(pattern) / 4:
+                break
+            yield e
diff --git a/nemubot/tools/test_human.py b/nemubot/tools/test_human.py
index 06b48d8..8ebdd49 100644
--- a/nemubot/tools/test_human.py
+++ b/nemubot/tools/test_human.py
@@ -1,6 +1,6 @@
 import unittest
 
-from nemubot.tools.human import size, word_distance
+from nemubot.tools.human import guess, size, word_distance
 
 class TestHuman(unittest.TestCase):
 
@@ -31,6 +31,10 @@ class TestHuman(unittest.TestCase):
         self.assertEqual(word_distance("long", "short"), 4)
         self.assertEqual(word_distance("long", "short"), word_distance("short", "long"))
 
+    def test_guess(self):
+        self.assertListEqual([g for g in guess("drunk", ["eat", "drink"])], ["drink"])
+        self.assertListEqual([g for g in guess("drunk", ["long", "short"])], [])
+
 
 if __name__ == '__main__':
     unittest.main()