Why would you do that?

Why did you do that?

How could you do that?

I don't understand the differences. I want to know how to use these phrases in the conversation.


In conversation tone of voice may be of great importance

Why did you do that?

This could be a simple question, but it could also be a rhetorical question meaning "You should not have done that". Stress on the word "do", with falling intonation on that could indicate the rhetorical question.

The others questions also could sound like rhetorical questions, with the same meaning

{husband} I've quit my job and put all our money into high-risk investments!

{wife} How could you do that!? With my earnings alone we won't be able to pay rent and buy food.

The wife isn't asking "How". It's a rhetorical question.

| improve this answer | |

As far as I understand, "would" in the fist sentence is a modal verb which is used to talk about things in the past that happened often or always. It's important to keep it in mind because the first sentence can be interpreted differently. So, let's get started:

  1. Why would you do that? = Why did you do it (frequently, repeatedly)?
  2. Why did you do that? (either frequently/repeatedly or once only)
  3. How could you do that? = How was it possible for you to do that? / How come you did that?
| improve this answer | |

Not the answer you're looking for? Browse other questions tagged or ask your own question.