diff --git a/mvc/models.py b/mvc/models.py
index 47571d4..ab95d6d 100644
--- a/mvc/models.py
+++ b/mvc/models.py
@@ -169,8 +169,8 @@ class VimModel:
 
     def CopyWord(self) -> None:
         start_index, end_index = self.WordUnderCursor()
-        line = self.displayBuffer[self.currentLine].data()
-        self.exchangeBuffer = line[start_index:end_index+1]
+        self.exchangeBuffer = self.displayBuffer[self.currentLine].\
+            substr(start_index, end_index-start_index).data()
 
     def Paste(self) -> None:
         self.displayBuffer[self.currentLine].insert(self.currentCol, self.exchangeBuffer)