American English:

In American English, "pants" is a general term used to describe any type of clothing worn from the waist to the ankles. This includes what are known as trousers in British English, as well as jeans, slacks, khakis, etc. In American English, "trousers" generally refers to a specific type of pants, often more formal than casual wear. They are typically worn in professional or dressier settings and are similar to what might be called "dress pants."
 
British English:

In British English, "pants" refers to underwear or undergarments for men or women, which is equivalent to what Americans would call "underpants" or "panties." In British English, "trousers" is the standard term used to describe what Americans call "pants." It encompasses all types of pants, including both casual and formal styles. 

在英式與美式英文裡，pants/trousers 指的都是「長褲」，只是用字習慣不同：美式英文通常說 "pants"，英式英文則偏好 "trousers"。舉例來說，美國朋友會說："I bought new pants yesterday and they fit perfectly.", 而英國朋友可能說："He ironed his trousers before the interview." 使用時注意複數型態，因為褲子有兩條褲管，通常直接用複數；如果你在英國把 "pants" 說成內褲可別嚇到對方，因為在那裡 "pants" 也常指內衣褲喔！所以旅行或寫作時，先想想你的讀者是哪一邊，以免造成尷尬。

"Pull (it) up" is a common phrase used when talking about adjusting clothes, especially when something is slipping down. For example, if your jeans are too loose and start sliding down, you might say, "I need to pull up my jeans." It's also used for things like socks, sleeves, or even a strapless dress. Imagine you're helping a friend get ready, and their dress keeps slipping—you might say, "Hey, your dress is falling down. Pull it up a little!" It's just a simple way to tell someone to lift their clothing back into place.

在日常英語裡，pull it up 通常有兩種常見用法：第一種是在使用電腦或手機時，表示「把某個檔案或資訊叫出來、打開來看看」，好像你用手把東西往上拉到眼前一樣；例如朋友可能說："Can you pull it up on your phone so we can check the schedule?" 第二種則是字面上的「把它往上拉」，像是拉拉鍊、拉窗簾或把褲子往上提；例如："My pants are falling down—let me pull them up." 無論是哪一種，核心概念都是把某樣東西移動到一個更高或更顯眼的位置，所以記得只要想到「往上拉」或「把畫面叫出來」，就能快速抓到 pull it up 的感覺。