题目

Mr.Green is looking forward ________ a big house for his family.A．to buying?B．to buyC．buy ? D．buying  答案：【答案】A【解析】试题分析：句意：格林先生期望着给他的家人买一座大房子。look forward to doing sth“期望做某事”，故此处用动名词buying。故选A。如图，把△ABC沿线段DE折叠，使点A落在点F处，BC∥DE，若∠B=50°，则∠BDF=________°．