Если необходимо сделать акцекнт на том, что уровень В1 занят супермаркетом, почему бы так буквально и не перевести?

supermarket AZBUKA VKUSA occupies level B1

такая конструкция вполне естественна:

"The traditional suburban supermarket occupies a large amount of floor space, usually on a single level, and is situated near a residential area in order to ..."

http://en.wikipedia.org/wiki/Supermarket

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Note added at 25 mins (2008-09-19 06:53:17 GMT)
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если надо подчеркнуть, что супермаркетом занят весь уровень, то будет так:

supermarket AZBUKA VKUSA occupies entire level B1

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Note added at 34 mins (2008-09-19 07:02:02 GMT)
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Тогда так:

"The level B1 is occupied by supermarket AZBUKA VKUSA"

"The rest of this floor is occupied by offices, committee rooms, and press galleries. The fourth floor and the basement/terrace level of the Capitol are ..."
ttp://www.aoc.gov/cc/capitol/index.cfm


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Note added at 37 mins (2008-09-19 07:04:44 GMT)
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Ещё примеры:

"The 6th floor is occupied by only one able bodied employee. The employee on the 6th floor is responsible for positioning the conveyor belt over the chip bin ..."
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_tabl...

"While the ground floor is occupied by public areas, such as hotel lobby, restaurant, bar and shops, the upper volumes are solely occupied by hotel rooms and ..."
http://www.architecture-page.com/go/projects/aparthotel-melc...