The Hebrew phrase הוא ישן במשך תשע שעות has been translated by DL as 'He is sleeping for nine hours.' This is literally correct but what it really means in English is 'He has been sleeping for nine hours', but this was marked as incorrect. It's a correct idiomatic English translation and should marked correct. In fact, 'has been sleeping' is in the present perfect tense, so it is an accurate translation. No-one would actually say 'He is sleeping for nine hours' in English - it's just not the way English speakers speak, nor is it grammatically correct in English.