Topic 1: Increasing travels between countries enable people to learn different cultures or to increase tension between people from different countries

 
79.
 
Population 
+ 
adult,  ageing,  Asian,  elderly,  foreign-born,  general,  global,  homeless, 
indigenous, local, native, rural, teenage, urban, working
 
80.
 
Problem 
+ 
economic,  emotional,  financial,  immediate,  major,  mental,  personal, 
practical, serious, social, technical
 
81.
 
Purpose 
+ 
dual, general, main, medical, particular, practical, present, primary, sole, 
useful
 
82.
 
Reason 
+ 
apparent,  good,  legal,  main,  major,  obvious,  personal,  possible,  real, 
special
 
83.
 
Relationship  + 
causal, close, direct, effective, family, human, personal, reciprocal, same-
sex, social, special, strong, working
 
84.