Why can’t the answer also be piensas as well as crees?
As I understand it, the software has been developed to accept one answer and only one answer for each sentence. Otherwise the application’s design would become more complex, and thus more error prone, expensive to develop and maintain AND still have the same problem unless you accept all the possible synonyms every cloze word has.
In short, it’s a design constraint.
Thank you! Just wanted to make sure I wasn’t incorrect