blakey wrote:can somebody explain when ли е is used at the end of a sentence and when it is used in the middle of one
Ah well, now there's a tricky one. But first, keep in mind that ли doesn't have to be with e - e is itself a verb, the third person singular of the verb "to be" (аз съм, ти си, той/тя/то е etc). Ли is the little word which turns a statement into a question. And because a statement needs a verb, it generally attaches itself to the verb - so that instead of making a statement based on a verb, you are asking a question using that verb. Such as "Искаш ли още една бира?" (Do you want another beer?) - not "Искаш още една бира ли?".
But as I've discovered over the years, there are exceptions to the general rule. One useful one to remember is that if the verb is the last word in the sentence/statement, then "ли" will generally precede it - as in the commonly asked question "Добре ли си?" (Are you ok?). It would sound wrong to a Bulgarian to ask "Добре си ли?"
Also, it seems to me that sometimes ли is put after the noun, rather than the verb, to emphasise what is being asked. But right now I can't think of an example of this - perhaps others here can.
My own thinking is that you can't go too far wrong using the general rule - attach ли to the verb - after the verb if there's more to come in the sentence, before the verb if its the last word in the sentence.
I stand back and await correction.