Adopt @CaseyCarter's suggestion

Co-authored-by: Casey Carter <cartec69@gmail.com>

Author: frederick-vs-ja

source/classes.tex

@@ -3668,10 +3668,10 @@
 \pnum
 \indextext{base class!ambiguous}%
 \indextext{base class!unambiguous}%
-When class \tcode{B} is a possibly indirect base class of class \tcode{D},
-if there is only one possibly indirect base class subobject of type \tcode{B}
-of a \tcode{D} object, \tcode{B} is an \defnadj{unambiguous}{base class} of \tcode{D},
-otherwise, \tcode{B} is an \defnadj{ambiguous}{base class} of \tcode{D}.
+If an object of class \tcode{D} has a single base class subobject of type \tcode{B},
+\tcode{B} is an \defnadj{unambiguous}{base class} of \tcode{D}.
+If an object of class \tcode{D} has more than one base class subobject of type \tcode{B},
+\tcode{B} is an \defnadj{ambiguous}{base class} of \tcode{D}.
 \begin{example}
 \begin{codeblock}
 class B { @\commentellip@ };