Using already in questions to express surprise makes sense. Is there any reference literature where I could find this rule? It's kind of a problem, since in all the grammar books I have it is said that Already is not used in questions, but in several conversations in textbooks I did see the questions worded as "Have you already done it?"

Thanks in advance!

Hello Sven63, JoshuaChase and NataliyaUkr

You all raised the question of when or how to use both adverbs: ALREADY and YET. In fact they are different though both are commonly used with the Present Perfect. Look at these two examples:

       1)

  RIDHA ABDELLAOUI : Have you finished doing the exercise? ( I'm expecting Some may say"Yes", others "No".)

  MY LEARNERS          : No, sir. We haven't finished yet. (As if they said you did not give us enough time, Wait!)

        2)

  RIDHA ABDELLAOUI : Haven't you finished yet? (I'm expecting all to say"Yes" because they had enough time.)

  MY LEARNERS          : We have already finished. (As if they said we took our time and we did it.)

Here are three links that may help you:

                     a) http://answers.yahoo.com/question/index?qid=20070726095220AApM0Ep

                      b) http://www.eclecticenglish.com/grammar/PresentPerfect1C.html

                      c) http://www.britishcouncil.org/learnenglish-central-grammar-adverb-already-yet-still.htm

But note that Already can be used with the Past Simple. Look at these examples:

            I          : Did you wash the trousers?

            My wife: Not yet

            I          : Why? (because I told her yesterday to wash them.)

            My wife : You didn't buy the washing powder.

            I           : I already bought it. I left it in the rear box of the car.