题目

Is ____ three hours ____ the boy___ family is poor to come to school on foot? A. it, that, shoes  B. it, when, that  C. it for, that it takes, whose  D. it, that it takes, whose 答案：D给你两个开关、两个灯泡、两节干电池和若干导线，如图，设计电路使每个开关只控制一个灯泡，画出电路图，连接实物电路．