diff --git a/Doc/Sd1/appendix.xml b/Doc/Sd1/appendix.xml
index 18b77ffa07a9eeb29b3138618e00d730b0658996..e3a6c2d415f55b6a7754d81f686f852b51d81b0f 100644
--- a/Doc/Sd1/appendix.xml
+++ b/Doc/Sd1/appendix.xml
@@ -852,9 +852,9 @@ public void test_400() {
 
         <para>Every <abbrev
         xlink:href="https://en.wikipedia.org/wiki/Reverse_Polish_notation">RPN</abbrev>
-        expression may be viewed as a token sequence each having both a token
-        type and a token content. Consider the following expression
-        <code>-1.34 0.34 + sqrt</code> consisting of four tokens:</para>
+        expression may be viewed as a sequence of tokens each having both a
+        type and a content. Consider the following expression <code>-1.34 0.34
+        + sqrt</code> consisting of four tokens:</para>
 
         <screen>Type: Double | Type: Double| Type: Binary plus | Type: square Function
              |             |       operator    |       root