题目

 Living in a highly ______ society, you definitely have to arm yourself with as much knowledge as possible. A. attractive           B. favorable           C. communicative   D. competitive 答案：D如图，已知AB∥CD，AD、BC相交于点E，F为EC上一点，且∠EAF=∠C．（1）求证：△AFE∽△BFA；（2）求证：AF2=EF•FB．