which is a compound sentence? “the city’s stage and its velvet curtains were a gift from a wealthy patron and his wife.” “cell phones and the new technology that has accompanied them have changed the world.”

Second sentence “cell phones and the new technology that had accompanied them have changed the world”.

A compound sentence consists of two or more independent clauses joined with a comma and coordinating conjunction.

The phrase that revels setting is whisper because it shows what he is doing .

This is a complete adjective clause.