Insert missing pronoun
diff --git a/Doc/tut/glossary.tex b/Doc/tut/glossary.tex
index 8cf0949..1678f76 100644
--- a/Doc/tut/glossary.tex
+++ b/Doc/tut/glossary.tex
@@ -62,8 +62,8 @@
latter notation; the imaginary part is written with a {}\code{j} suffix,
e.g., {}\code{3+1j}. To get access to complex equivalents of the
{}\module{math} module, use {}\module{cmath}. Use of complex numbers is a
-fairy advanced mathematical feature. If you're not aware of a need for it's
-almost certain you can safely ignore them.
+fairy advanced mathematical feature. If you're not aware of a need for them,
+it's almost certain you can safely ignore them.
\index{descriptor}
\item[descriptor]