White for or since. Since 2002 ... yesterday ... six days

since 2002;

I have been studying at academy since 2002. - Она учится в академии с 2002 года.

since yesterday;

She has been travelling since yesterday. - Она путешествует с вчерашнего дня.

for six days;

They have been learning this poem for six days. - Они учат этот стих в течение шести дней.