A complex sentence is a sentence consisting of an independent clause and a subordinating clause. Or, to put it more simply, complex sentences involve more than just a straightforward noun + verb. Complex sentences include extra phrases added to a base sentence, but which cannot stand alone as a sentence. For example:
Published 4:00 am, Thursday, January 9, 1997. 1997-01-09 04:00:00 PDT Yosemite National Park -- Yosemite Valley is slowly drying out after what park rangers are calling the worst flood here in recorded history, leaving behind hundreds of upturned tent-cabins and acres of wrecked camping sites.
Story highlights. (CNN)Environmental groups warned nearly 12 years ago that the nation's tallest dam in California was an imminent disaster. They worried that heavy rain and fast-rising waters could overwhelm the main concrete spillway of the Oroville Dam, overflow the emergency spillway and flood communities downstream. They were ignored.