"The author wrote his thoughts on the economic problem."
Translation:El autor escribió sus reflexiones sobre el problema económico.
Yes, because they both are translated into thoughts, but they are not synonyms. pensamiento is a direct thought (for instance I'm cold today), whereas reflexión is a complex process of thinking about a problem.
Instead of 'reflexiones', I used pensamientos and it was marked wrong. Any special reason?
Perhaps you had something else in the sentence that was incorrect, as I used pensamientos and it was fine. Maybe you wrote la problema instead of el? I did that the first time around. Or maybe you didn't conjugate escribir in the past tense?
using the word bank did not provide enough words or ones deemed incorrect. Not possible to use typewriter & wordbank to fill the blanks