I want to know the answer to the following question:
When forming compound tenses in Spanish, what auxiliary is no longer used?
All the background I'm provided with is that "However, when it comes to phonological structures, Italian and Spanish have undergone less change than French, with the result that some native speakers of Italian and Spanish may attain a degree of mutual comprehension that permits extensive communication.[citation needed]". Is that enough to answer the question?
Answer: no