Complex sentence: She headed on out of the harbor to patrol offshore for the next week, then joined "Lexington" (CV-2) in the attempt to relieve doomed Wake Island, captured by the Japanese before "Lexington" 's force could bring aid.
Split into simpler sentences: She headed on out of the harbor to patrol offshore for the next week, then joined "Lexington" (CV-2) in the attempt to relieve doomed Wake Island. But Wake was captured by the Japanese before "Lexington" 's force could bring aid.