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.
Housekeeping Camp. A Housekeeping Camp lodging unit. Located in the Yosemite Valley, Housekeeping Camp is one of the cheapest lodging options for visitors to Yosemite National Park. The camp is open from April through October and is one of the most popular places to stay in the valley. Reservations typically fill up on the first day they become available.