Cosmetics.

doc/manual/mtime.tex

@@ -345,7 +345,7 @@ Time spans can be initialized from seconds and milliseconds integer values:
 \end{fortran}
 \end{flushleft}
 
-Conversely, \mtime intervals may be converted by
+Conversely, \mtime intervals can be converted with
 \vspace*{-1.em}%
 \begin{flushleft}
 \begin{fortran}