what questions do direct objects answer?
¿conoces a la novia de tu mejor amigo?
1 Answer
Direct object not only not answer questions, but also give misleading answers. Old grammars used to say that direct objects answer the question "What...?", and sometimes "Who...?", but the number of cases where this fails miserably is enough to abandon this illogical approach:
¿Qué quieres? -> The answer will be the direct object.
¿Qué te gusta? -> The answer will be the subject.
¿Qué es eso? -> The answer will be the "atributo".
¿A quién quieres? -> The answer will be the direct object.
¿A quién se lo has dado? -> The answer will be the indirect object.
Do not ask words, because they will let you down.