19.1 Úgy szokták tanítani, hogy a since pontos időpont, a for pedig határozatlan. Na most én így soha nem tudtam eldönteni. Úgy sikerült "megtanulni", hogy a
for = -ja/ve... (15 éve)
since = óta (hétfő óta)

3. for (15 éve)
4. since (7 óra óta)
5. since (1947 óta)
6. for (20 perce)
7. for (sok éve)
8. for (sok ideje) since (október óta)

19.2 Át is írhatod őket hogy igazak legyenek, de a lényege, hogy jó legyen, nem az hogy igaz.
Mikor voltál utoljára beteg? - Six months ago.
Mikor voltál utoljára moziban? - Two years ago.
Mikor ültél utoljára autóban? - A week ago.
Mikor voltál utoljára nyaralni? - A year ago.

19.3
Ha past simple (ige+-d/ed) - ago
Ha present perfect (have/has+ige 3) - for
for 20 years.
20 years ago.
ten minutes ago.
an hour ago.
for six months.
for a long time?
a few days ago.

19.4
He has been here since Tuesday.
It's been raining for an hour.
I've known Sue for two years.
I've had a camera since 1989.
They have been married for six months.
She has been learning medicine for three years.
Dave has played the piano since he was seven years old.

19.5 Itt is ugyan az érvényes mint a 19,2-nél.
I've lived here since I can remember.
I've been walking for an hour.
I've been learning English since 1st grade.
I've known Emma for 7 years. (Ide írhatsz akár oszt. társat is.)
I've had a bike since 2015.