里用英语怎么说介词是用on还是用in

对于平面的物体,比如照片,操场这一类的,在上面用on,在里面用in
比如：
照片上摞了一张报纸
there's
a
piece
of
newspaper
on
the
photo.
照片上有一只狗
There
is
a
dog
in
the
photo.
孩子们在操场上活动
Kids
are
playing
on
the
playground.
皮箱被埋在操场
the
suitcase
is
berried
in/under
the
playground.通常都用under,用in的很少,但是一定不能用on
在小镇里英文：
in
town
介词是用in
例句
1.辛普森太太做的汤在小镇里是最好的.
Mrs.
Simpson
made
the
best
soup
in
town
2.你问他们下一次愿不愿意在小镇里度假没有?
Did
you
ask
them
if
they
would
spend
their
holidays
in
town
next
time
3.他们住在一个小镇里.
They
live
in
a
small
town.