Use of English PRO

Commuting - that is, to (0) SAY travelling from one region to another (1) ............ work before travelling back to where you live on a regular basis - has been possible since the advent of the railway. However, in recent times it has become the (2) ............ as opposed to the exception, as people increasingly move out of the cities and into more suburban settings. Let's (3) ............ London as an example. Most people who work in what is considered to be the central part of the city must commute due to the excessive cost of living in (4) ............ a place. A journey of at least one hour on public transport is by no (5) ............ uncommon, as the use of private cars has been reduced greatly by anti-pollution and congestion legislation. On the more extreme side of things are stories of business people traveling up to three hours (6) ............ way every day rather than living in the capital city. You might expect that these journeys would be made by train, but recently the lower cost of air travel has made it widely possible for people with relatively normal incomes to travel from the (7) ............ of Barcelona to London or Zurich, for example, thus (8) ............ advantage of the higher standard of living and better weather of their home city while earning a higher salary obtainable in one of those financial hubs.