Нужно употребить либо в present perfect, либо в present perfect continuous 15. your eyes are red. you (cry)? 16. where on earth you (be)? i (wait) for so long! 17. bill, you have got a black eye again. you (fight)? 18. do you think george (finish) the translation? he (write) for so long! 19. i think i can smell smoke on debbie's clothes. i'm sure she (smoke). 20. here you are! i (look for) you everywhere. where you (be)?

15.Crying;16. Was/Waiting; 17. Fighting; 18.Finished/Writing; 19. Smoking; 20. Looking for/Was.

15) You have been crying?( правильнее в вопросительном предложении будет: Have you been crying?)
16) Where on earth you have been?
I have been waiting for so long!
17) You have been fighting? (Тоже самое, что и в 15. С вопросительным предложением)
18)George has finished. He has been writing
19) She has smoked
20) I have been looking for you. Where HAVE you BEEN ( так же как и в 15 и в 17₽