diff --git a/managing-os/pentesting.md b/managing-os/pentesting.md
index a4751f41..cb85ba17 100644
--- a/managing-os/pentesting.md
+++ b/managing-os/pentesting.md
@@ -27,4 +27,4 @@ The following install instructions explain how to setup a penetration testing di
 Using Qubes OS to host a "hacking" laboratory
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-Qubes OS is a hypervisor based operating system. Qubes OS can host various operating systems such as Linux, Unix or Windows and run them parallel. Qubes OS can therefor be used to host your own "hacking" laboratory.
+Qubes OS is a hypervisor based operating system. Qubes OS can host various operating systems such as Linux, Unix or Windows and run them in parallel. Qubes OS can therefor be used to host your own "hacking" laboratory.