题干
The old man told us a humorous story. And it made us laugh.
A：funny
B：strange
C：special
答案(点此获取答案解析）
A
The old man told us a humorous story. And it made us laugh.
A：funny
B：strange
C：special
物体上升到某一高度时,其重力势能恰好是动能的2倍，此高度为（以地面为零势能面
）（ ）
