Thread: intrumental or accusative for the word 'магазином'

Some clarification: "за + accusative" means direction. Therefore, your choice is "заехать за магазин" (it means from point A, which is not behind the shop, to point B, which is behind the shop).

However, "за + instrumental" means location. "Я сейчас за магазином" = I am behind the shop now. It can also mean motion like "проехать за магазином" (to drive along from point A, which is already behind the shop, to point B, which is also behind the shop).

The verb "заехать" can only be used with "за магазин" (to where?).
The verb "проехать" can be used with both "за магазин" and "за магазином", but the meaning is different:
Я проехал за магазин - I started driving not behind the shop, but then I moved to behind the shop.
Я проехал за магазином - My whole path was behind the shop.

Another meaning of "заехать за + instrumental", as Doomer noted, is to make a stop to pick up something (or someone):
Он заехал за мной. - He came to my place (on his way to somewhere), made a stop to pick me up, and continued driving.
Он заехал в магазин за продуктами. - He made a stop at a shop (on his way to somewhere) for some food.

Originally Posted by Боб Уайтман

Он заехал в магазин за продуктами. - He made a stop at a shop (on his way to somewhere) for some food.

FYI
In American English продукты is groceries
Food usually means meal that is ready to eat

Also shop is rarely used in this meaning. It is "store" now (in the US English)
Shop is usually referring to something rather small and can also mean мастерская but is widely used in British English

IMHO

so what word do you use for store and shop?
how do you use them?

Originally Posted by tiudavidharris

so what word do you use for store and shop?
how do you use them?

Are you asking about Russian or American English? Did not get you.