area 做什么时候可数!?

大侠给我讲讲 area 的单复数情况!?

谢谢

作面积时，不可数； 作区域，领域时可数

这是可数情况
1

a particular part of a country, town etc
in an area
Only cheeses made in this area may be labelled 'Roquefort.'
There were over 2 inches of rain in coastal areas .
area of
a working-class area of Birmingham Many areas of Africa have suffered severe drought this year.
a rural area (=countryside) of woodlands and fields Crime rates are significantly higher in urban areas (=towns, cities etc) . The police have searched the farm and the surrounding area (=the area around it) . children from the local area a residential area of the town
2
a part of a house, office, garden etc that is used for a particular purpose
a no-smoking area Their apartment has a large kitchen area . Come through into the dining area . the reception area of the hotel a storage area on the ground floor
3
a particular subject, range of activities, or group of related subjects
The course covers three main subject areas . This study has clearly identified a major problem area for the National Health Service. We're funding research into new areas such as law enforcement technology.
area of
reforms in the key areas of health and education
4
the amount of space that a flat surface or shape covers
area of
an area of 2,000 square miles a formula to calculate the area of a circle