单选题：Migrant（移民的）Workers In the past twenty years，there has been

Migrant（移民的）Workers In the past twenty years，there has been an increasing tendency for workers to move from one country to another．While some countries have restricted most_____（51）to local people，others have attracted and welcomed migrant workers．This is particularly the case in the Middle East，_____（52）increased oil incomes have enabled many countries to call in outsiders to improve local facilities．Thus the Middle East has attracted oil．workers_____（53）the U．S．A．and Europe．It has brought in workers from many countries,_____（54） South Korea and Japan．
In view of the difficult living and working_____（55）in the Middle East，it is not surprising that the pay is high to attract suitable workers．Many engineers and technicians call_____（56）at least twice as much money in the Middle East as they Can in their own country, and this is a major_____（57）．
Sometimes a disadvantage has a compensating（补偿的）advantage．For example，the_____（58）living conditions often lead to increased friendship when workers have to_____（59）on each other for safety and comfort．In a similar way, many migrant workers Can save large sums of money partly because of the_____（60）of entertainment facilities．
The work is often complex and full of problems but this merely_____（61） I greater challenge to engineers who prefer to find solutions to problems rather than do routine work in their home country．
One major problem which_____（62） migrant workers in the Middle East is that their jobs are temporary ones．They are nearly always on_____（63），so it is not easy for them to plan ahead with great confidence．This is to be_____（64） since no country welcomes a large number of foreign workers as permanent residents．In any_____（65）,migrant workers accept this disadvantage，along with others，because of the considerable financial benefits which they receive． A．cases
B．jobs
C．activities
D．uses