Cách sử dụng
The word "upon" is used to show that something happens at the same time as another thing or shortly after it. It can also be used to indicate that something is happening because of something else. For example, you might say, "Upon arriving at the party, I realized I forgot my phone," which means that as soon as you got to the party, you noticed that your phone was missing. Or, you might say, "Upon hearing the news, she burst into tears," which means that when she heard the news, she immediately started crying.Overall, "upon" is a more formal word than "on" or "when," so it is often used in writing or formal speech.