题目

It was raining heavily. The teacher made the children ________ in the classroom.   A. stay        B. to stay      C. staying        D. stayed 答案：A我国东汉时期就有摩擦琥珀能吸引轻小物体的记载，则下列说法正确的是（ ）A．两悬挂的泡沫小球经毛皮摩擦后靠近时会相互吸引B．玻璃棒与丝绸摩擦时玻璃棒带正电C．摩擦过程可以创造电荷D．原子对外不显电性说明原子内部没有电荷