1. 钢笔
    A pen is a long thin object which you use to write in ink.

2. 写；书写
    If someone pens a letter, article, or book, they write it.

    e.g. I really intended to pen this letter to you early this morning...
           我真的打算今天一大早给你写这封信的。
    e.g. She penned a short memo to his private secretary.
           她给他的私人秘书写了一份简短的备忘录。

3. 栏；圈；棚
    A pen is also a small area with a fence round it in which farm animals are kept for a short time.

    e.g. ...a holding pen for sheep...
           暂时搭建的羊圈
    e.g. He wasn't sure exactly how a fox could have got into the sheep's pen.
           他不是十分确定狐狸是怎么进入羊圈的。

4. 把…关起来；把…圈起来
    If people or animals are penned somewhere or are penned up, they are forced to remain in a very small area.

    e.g. ...to drive the cattle back to the house so they could be milked and penned for the night...
           将牛群赶回家，这样就能挤奶并将其关进牛棚过夜
    e.g. The goats are penned in and fodder has to be cut and carried each day...
           山羊被关进圈里，每天都得铡草运料。

5. 监狱
    People sometimes say the pen to refer to a prison.

6. 动笔；下笔
    If you put pen to paper, you write something.

    e.g. Whenever he put pen to paper he was at a loss for the right words to break the news.
           他每次一提笔就不知道如何措辞透露这个消息。