• This is an active area of research.

• The electronic structure of the nitrogen molecule has been the subject (or theme) of much investigation.

• The shapes of such curves have long been subjects for study.

I

см. тж. в данной области; в области; во всей области; относиться к области; сфера

• This is an area of spectroscopy in which ...

• Developmental work is being carried out in two new areas (or fields, or spheres).

• This skill is necessary to every department of life.

• To extend this linear concept into the domain of nonlinear systems, ...

• In several domains of science ...

• Thus we enter into the territory of metaphysics.

• New aspects of multiple coloumb excitation are among the realms that can be advantageously explored.

II

см. тж. в диапазоне; в интервале

• The flux is uniform over the whole area.

• To supply power in remote locations (or regions, or areas), such as the Arctic, ...