Upgradation
升级；改善；提高
🗣️ 情景例句
I'm leaving for Beijing on a four-day tour.
我马上要去北京旅游4天。
We are mutual friends.
我们彼此是朋友。
But as the paper moved from side to side under the pen point,
由于纸在笔尖下来回运动，