Read the sentence. Before taking any drastic measures, the writer decided to carefully review his novel to see if there was anything he could salvage. What is the complete predicate of the sentence? Before taking any drastic measures, the writer the writer decided to carefully review his novel decided to carefully review his novel to see if there was anything he could salvage the writer decided to carefully review his novel to see if there was anything he could salvage

The complete predicate of the sentence is decided to carefully review his novel to see if there was anything he could salvage.

The main verb in this predicate would be decided. However, it would be incomplete without more information (decided what?), so we've got the phrase to carefully review his novel, which again may or may not (but in this case does) require more information (to review the novel why?), so there is another additional phrase to see if there was anything he could salvage.