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

 
18.
 
Care 
+ 
extra, intensive, medical, nursing, personal, primary, private, reasonable, 
special
 
19.
 
Cause 
+ 
important,  likely,  main,  major,  noble,  possible,  real,  reasonable, 
underlying, worthy
 
20.
 
Characteristic 
+ 
defining,  demographic,  distinctive,  distinguishing,  essential, 
general, important, individual, main, particular, personal, physical, social, 
special, unique
 
21.
 
Child 
+ 
eldest, grown-up, old, only, small, young, youngest 
22.
 
Circumstance + 
certain,  different,  difficult,  economic,  exceptional,  extreme,  financial, 
normal, particular, political, present, social, special, unforeseen
 
23.