It seems to me that these simple past forms, with certain adverbs, such as "fós", can correspond to English present perfect (have/has + past participle) eg "Has she reached the college yet?", particularly in British English. This alternative is generally rejected in these exercises.
Such translations should certainly be allowed, since they are often the most natural option in English, as you say. 'Has she reached the college yet?' sounds much better to me than 'Did she reach the college yet?' If you report such oversights, they will probably be corrected.