题目

He asked us to _______ him _______carrying out their plan. A. assist; with    B. help; to      C. assist; in      D. help; with 答案：C1．已知：如图，E、F为平行四边形ABCD对角线AC上两点，且AE=CF，连接DE、EB、BF、FD，求证：四边形DEBF为平行四边形．