题目

More than half of the participants said that getting married was not an important___________ for becoming an adult.A.tension B.restriction C.circulation D.criterion 答案：【答案】D【解析】考查名词。句意：超过一半的受访者表示，结婚并不是成为成年人的重要标准。A. tension紧张；B. restriction限制，约束；C. circulation流通，传播；D. criterion标准，准则。根据getting married和becoming an adult可知，结婚是成为一个成年人的“准则”。故选D。（08年太原市一模文） 函数的定义域是             。