Non-specified "you" form- dealing with ambiguity

Question

The question did not specify to use the tú or usted form, and in a later question, it did specify "tú."  So I typed "leyó", but was marked wrong. I had "leiste" until I saw "tú" specified later, so I changed it.  Either both should be right or it should be specified, to reduce frustration.  I can see if you were talking to a family member or close friend (in an obvious context), then it should be expected to be "tú." But this was quite ambiguous- you could have loaned a book to a friend or a colleague or boss.

Answer

Hola Jeffrey

I checked all the test-questions here and they all have an explicit pronoun showing clearly on the sentence, either tú, usted, vosotros or ustedes, so there is no ambiguity. If you see the subject "tú" the only possible answer is "leíste" because the pronoun tú is already telling you that it is the informal you, and the same for the others, for usted you need leyó, for vosotros you need leísteis and for ustedes you need leyeron.

I hope this clarified it.

Saludos cordiales.

Inma