Drop a line是什麼意思

"Drop a line" is an English idiom that means to write a short letter or message to someone. It implies a casual and brief communication, often used between friends or acquaintances to keep in touch or to say hello. Here's an example of how it might be used in a conversation:

"I should really drop a line to my old roommate and see how she's doing."

In this context, the person is thinking of sending a quick note to their former roommate to catch up. The phrase is casual and suggests a simple, informal communication rather than a formal or lengthy letter.