题目

 (10·辽宁D篇) On May 23,1989, Stefania Follini came out from a cave at Carlsbad, New Mexico. She hadn’t seen the sun for eighteen and a half weeks. Stefania was in a research program, and the scientists in the program were studying body rhythms (节奏)。In this experiment Stefania had spent 130 days in a cave, 30 feet in depth. During her time in the cave, Stefania had been completely alone except for two white mice. Her living place had been very comfortable, but there had been nothing to fell her the time. She’d had no clock or watches, no television or radio. There had be我国糖料作物的分布具有“南蔗北甜”的特点，它反映了农业生产具有 A．季节性　　B．周期性　　C．随意性　　D．地域性