🧩 词语组成解析
upon
[ə'pɑn]
prep. 在…上面;当…时候;
🗣️ 情景例句
If someone doesn't buy it before then,
如果在此之前没有人买走的话。
Experience is the best teacher.
经验是良师。
At the head of the queue was an old woman.
排头的是位老太太。