Questions about Direct Object Pronouns
Q: Why is it Il me voit and NOT Il voit moi?
Most pronouns come before the verb in French. This includes direct object pronouns.
Q: Why is it Elle les a vus and NOT Elle les a vu?
The past participle must agree in gender and number with the direct object pronoun. In this case, it is plural.
Q: Why is it je l'aime and NOT je lui aime?
When deciding to choose between lui/leur and le/la/les, replace the pronoun with a noun after the verb, e.g.: J'aime mon père, je parle à ma soeur. In the first sentence, we see that mon père comes right after the verb (there is no à in between). As such, we know that lui is not possible (since lui goes with verbs followed by à. In the second sentence (je parle à ma soeur), however, the verb is followed first by à. As such, lui is the correct pronoun (je lui parle).
Q: Why is it Je m'intéresse au travail and NOT Je me intéresse au travail
French doesn't like to have two vowels in a row. As such, the direct object me changes to m' since the next word begins with "i".