phrase
B2
moving in a direction that rises and then falls
The kids were jumping up and down with excitement.
孩子们兴奋地跳上跳下。
B2
moving from one end to the other and back
He was pacing up and down the hallway, waiting for the news.
他在走廊里来回踱步，等待消息。
translation
上下, 来回