题目

如图，P为平行四边形ABCD边AD上一点，E、F分别为PB、PC的中点，ΔPEF、ΔPDC、ΔPAB的面积分别为S、S1、S2。若S=2，则S1+S2=。 答案：【1】8Do you think the problem is ______? If you think hard, you'll find it ______ to work out. [     ]A. hard; easyB. easy; hard C. hardly; easily D. hard; easily