题目

29. For English teachers ________ a more effective role in teaching, they must make every effort to raise students’ cross-cultural awareness. A. to play             B. playing                C. having played   D. Play 答案：A13．把一张矩形纸片（矩形ABCD）按如图方式折叠，使顶点B和点D重合，折痕为EF（1）问四边形DEBF是什么特殊四边形？说明理由．（2）若AB=3cm，BC=5cm，求五边形A′EFCD的面积．