题目

       WASHINGTON ,Jan. 21—“I want to be a builder. I want to build houses and buildings for the homeless,” said Aman Efrem ,a third-grade student from Hearst Elementary in Washington. D.C. For another student, Azalea Westray ,the dream is “that all people stop violence” and “all people love and respect one another.”        The two were among various answers to the Washington Post’s blank filling to “My dream is…” when Americans observed the Martin Luther King’s Day Monday.        FromAtlanta to Chicago ,memorial services ,forums and rallies are h（2013•崇左）如图所示，正方形ABCD中，E是CD上一点，F在CB的延长线上，且DE=BF．（1）求证：△ADE≌△ABF；（2）问：将△ADE顺时针旋转多少度后与△ABF重合，旋转中心是什么？