I'm always in doubt whether to use HAVE or DID, for example:

- What's this noise? Have you knocked on the door?

or would it be

- What's this noise? Did you knock on the door?

Well, when do I use DID or HAVE ?

Thanks folks!

1 2
welcome to EnglishForward. Emotion: smile
You can also use the search function to search the forum for interesting threads (there's a search button in the top right corner of every page).

I would use "did", not "have". The simple past focus on something that happened and keeps that action separate from "now". So I would say:
What was that (noise)? Did you knock on the door?

The present perfect can be used with words like "yet", "already", "ever", etc., and it does not give the idea of "separate from now" as much as the simple past. It can also be used to report news or other information, when you don't want to focus on the past moment:
President Buch has died. He died this morning at 7, etc.
Notice the first verb is a present perfect (focus on the news, the fact, not the past), and the second is a simple past, because you are pointing out the time he died (focus on the past, "sepatateness from now").

The difference between these two verbs is one of the most difficult things to learn for every learner, so don't worry, it just takes time. There are also some slight differences in usage between American English and British English. You might want to search this forum for info about this (there are a lot of threads), or read something in a good ESL grammar.

And as you can see, I'm not a native speaker of English, so you'd better wait for some better advice. Emotion: smile
It's impossible to learn the difference between these in just one example -- or even in several hundred.

The short answer is that you use have when you are not interested in any specific time at which the event occurred, just that it occurred, and you use did when you want to characterize the event as having happened at some specific point in time.

In cases where you mention a time specifically, or even indirectly (in a when clause, for example), you have no choice; use the did form. In cases where you don't mention a specific time, you have a choice. Sometimes it just depends on how you are thinking of the event in your own mind.

Site Hint: Check out our list of pronunciation videos.
What are the differences between could, would, should, can, will, may??
You need to study your modals. Your question it too large for a single response. Why don't you find a few examples of when you aren't sure which one you should use and post them?
Click on the Modals button underneath your original posting and read those threads.
Students: Are you brave enough to let our tutors analyse your pronunciation?
I also want to know when should use did or have?
I always confused when to use did or have?
can you explain to me, what different between did or have..
you cooperation is highly appreciate,
hopefully you reply as well as.
Thank You...
Emotion: smile
Dear user,
I am at work having a "great time" so here you go:

Could = use it when you intend to say it was in your power to do it but you didn't for some reason.
Example: I could learn that lesson, but I didn't because I refuse to learn it.

Would = use it when you intend to say it was preferred by you but the final decision was, or is, not only up to you.
Example: I would like to learn, but I have no learning materials.

Should = use it when you intend to say you are supposed to do it, you are morally obligated.
Example: I should learn my lesson if I intend to graduate.

Can = use it when you intend to say is in your power to do it.
Example: I can learn. (I can drive. I can swim...)

Will = use it when you intend to make a future statement.
Example: I will learn tomorrow.

May = use it when you intend to say you can do it conditioned by something. You can see it as a replacement of maybe.
Example: I may learn if you will take me to the Cinema.

Keep in mind, this is explained for person 1...
Search for each word explained if you really intend to make the maximum out of those words.

PS: I could explain more, I explained this because I can, I may do it other time too, I would like to believe this will be helpful for you, I should get back to work now and I will go after the goodbye.

All the best.
Nice note explaining all in single sentence. Good summary!!
Students: We have free audio pronunciation exercises.
Show more