7класс. ! вставить since и for
1. how long has he been here? - for 20 minutes./ 2 o'clock.
2. how long have you known her? - last year./ ages.
3. how long hasn't she eaten fast food? - half a year./ april.
4. how long have you had your trainers? - summer./ a few months.
5. how long haven't they seen tess? - about a week./ friday.
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1. How long has he been here?- For 20 minutes (в течение 20 минут)./ since 2 o'clock (с двух часов).

2. How long have you known her?- since last year (с года)./ for ages (уже много лет).

3. How long hasn't she eaten fast food?- for half a year (в течение полугода)./ since April (с апреля).

4. How long have you had your trainers?- since summer ( с лета)./ for a few months (в течение нескольких месяцев).

5. How long haven't they seen Tess?- for about a week (около- в течение недели)./ since Friday.

for  используется — когда указывается промежуток времени

since -  точное время ( с двух часов, с года, с лета...)