You say 'Yay!' when something good happens and you feel happy right then — a friend passes an exam, the rain stops, the food arrives.

You say 'Yay!'你會說'Yay!' when something good happens and you feel happy right then當好事發生，你當下覺得開心的時候 — a friend passes an exam, the rain stops, the food arrives像朋友考試過了、雨停了、食物送到了。

It is a small shout of joy, not a word with a meaning you can put in another sentence; it stands alone, usually with an exclamation mark. It is warm and a bit childish, which is exactly why adults use it: it makes you sound light and friendly instead of serious.

It is a small shout of joy這是一種小小的歡呼, not a word with a meaning you can put in another sentence不是那種可以放進另一個句子裡使用的有意義的字; it stands alone, usually with an exclamation mark它自己獨立存在，通常帶著驚嘆號。It is warm and a bit childish它聽起來溫暖，又帶點孩子氣, which is exactly why adults use it這正是大人也會用它的原因: it makes you sound light and friendly instead of serious它會讓你聽起來輕鬆、友善，而不是嚴肅。

Very common in texting and online chat, where people also stretch it — 'yaaay' — or add it after news to show how they feel: 'She said yes, yay!' Because it sounds young, be careful at work; 'yay' in a message to your boss is fine between friendly colleagues but odd in a formal report.

Very common in texting and online chat在傳訊息和網路聊天裡很常見, where people also stretch it — 'yaaay'大家也會把它拉長，像'yaaay' — or add it after news to show how they feel或是在說完消息後加上它來表達心情: 'She said yes, yay!'像'She said yes, yay!'（她答應了，耶！）Because it sounds young, be careful at work因為聽起來很年輕，工作場合要小心; 'yay' in a message to your boss is fine between friendly colleagues but odd in a formal report在傳給老闆的訊息裡，'yay'用在熟識的同事之間還好，但用在正式報告裡就顯得奇怪。

There is also a sarcastic use, said flat and slow: 'Oh. Yay. More homework.' — meaning the opposite, and English speakers hear the difference from the tone.

There is also a sarcastic use還有一種諷刺的用法, said flat and slow用平淡、緩慢的語氣說出來: 'Oh. Yay. More homework.''Oh. Yay. More homework.'（喔。耶。又是作業。）— meaning the opposite意思正好相反, and English speakers hear the difference from the tone英語母語者是從語氣裡聽出這個差別的。

One more use you may meet: people hold two fingers apart and say 'yay big' or 'yay high' to mean 'about this big', showing the size with their hand.

One more use you may meet你可能還會遇到另一種用法: people hold two fingers apart and say 'yay big' or 'yay high'人們會把兩根手指張開，說'yay big'或'yay high' to mean 'about this big'意思是「大概這麼大」, showing the size with their hand用手比出大小。