题目

如果电梯上行20米记作＋20米，那么电梯下行20米记作米。 答案：【1】－20The money collected should be made good use __________ the people who suffered a lot in the terrible flood in Beijing on the night of July 21, 2012, which caused great losses．A．of helping B．to helpC．of to helpD．to helping