in their turn- in turn
Monopoly is- I'd use the plural here, or an indefinite article
high profit- profits sounds better to me
In the USA anti-trust laws operate to restrict monopolistic activity of cartels while in Britain all special arrangements and mergers are closely investigated by the Monopolies Commission.- I'd put a comma before 'while'
we have gathered here today- if this is a presentation/discussion, then this sounds a bit OTT- how about 'we are here today...'
is often not long- often does not last for long
The implementation of computers - I'd use introduction or spread
replacement of equipment - the
allows getting larger profit- makes it possible to get higher profits?
allows improving- allows us to improve