This exercise used to be the last one (=Part 6) in Paper 3 (Use of English) of the
ESOL Certificate in Advanced English (CAE) by the
University of Cambridge. From what I've read, it's not going to be a part of the test any longer. I've always thought it was the easiest part in Paper 3, so this might be the reason they got rid of it ... would you agree?

Below you've got a text from which
six phrases have been removed. These deleted phrases, together with three additional phrases, are placed below the text in random order. You must select the appropriate phrase for each gap in the text (rembember, you need only six of them!)
This task is designed to test awareness of discourse features which operate within and across a text, particularly features of cohesion and coherence.
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An odd place to live
A but extensive railway systems exist underground so why not huge cities?
B but architects make great efforts to mimic conditions above ground.
C but even being buried just for your working hours may not seem attractive.
D but human psychology makes this possible.
E but who would not accept these working conditions?
F but even the lowest floors get some sunlight.
G but technical difficulties cannot be overcome.
H but a special shower system can create the impression of rain.
I but is there an alternative to building up?