We can rewrite her sentences using direct object pronouns as follows: e l'ai oubliée dans le taxi.
What are direct object pronouns?
Direct object pronouns are words that replace direct objects in a sentence. They are used to make sentences shorter and more concise. In French, there are seven direct object pronouns: me (me), te (you), le/la (him/her/it), nous (us), vous (you), and les (them).
Some examples of how to use direct object pronouns in French are Je mange la pomme. (I eat the apple.) or Je la mange and Tu vois le chat. (You see the cat.) or Tu le vois.