题目内容:
Whathinderstheextensiveuseofrenewableenergysources?
A.Lackofadvancedstoringtechnology. B.Aneedforjointeffortsofscientists.
C.Ashortageofpracticalsupportfromthepublic.
D.Anunreliablemarketdemand.
参考答案:
答案解析: