著名的“洞穴喻”是谁提出的比喻（）
A、柏拉图
B、亚里士多德
C、亚历山大
D、普朗克
参考答案：A
Knowing how well he________ his future career,I feel confident that he will make a success. [ ]
A. is preparing for
B. is prepared for
C. prepares
D. prepares for
工程档案一般不少于( )套。
A．1
B．2
C．3
D．4
