A．do not have access to easy facilities because they live away from the city
B．have to pay a lot of money to employ people to do service work
C．take longer time to know each other because they are a scattered community
D．have to spend more money and time travelling to work every day

A．They were mostly inhabited by people who did not earn much.
B．They were usually not large enough to accommodate big families.
C．They were sold to people before necessary facilities were installed.
D．They provided playgrounds for children on the top of the buildings.