When a masculine noun is changed to feminine
for the pronoun (e.g. from 'he' to 'she' in example
above), a letter 'ta' with a sukun is added at the end of the
verb that follows i.e.,ذَهَبَ will be changed to
ذَهَبَتْ.
However when the noun is a
subject following a verb, and that noun is definite
(e.g. the girl) then instead of a 'ta with a
sukun a 'ta'
with the genitive case (kasra) is added to the verb i.e., the verb will beذَهَبَتِ الْبِنْتُinstead of
ذَهَبَتْ
الْبِنْتُ Lets take
some examples to better understand the rule: