grammar: comma for introductory phrase

diff --git a/docs/dnssec/modes-of-operation.rst b/docs/dnssec/modes-of-operation.rst
index 51efe233a67f2cd64053c855de6eeb81ec6ef455..1f6f42ad6107c184b3140824ff7472706c4be0a2 100644 (file)
--- a/docs/dnssec/modes-of-operation.rst
+++ b/docs/dnssec/modes-of-operation.rst
@@ -45,7 +45,7 @@ Zone Signing Keys (ZSKs). During normal operations, this means that only
 1 ZSK is 'active', and the other is inactive.
 
 Should it be desired to 'roll over' to a new key, both keys can
-temporarily be active (and used for signing), and after a while the old
+temporarily be active (and used for signing), and after a while, the old
 key can be deactivated. Subsequently it can be removed.
 
 As described above, there are several ways in which DNSSEC can deny the