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

Psychological + advantage, barrier, damage, disorder, distress, effect, factor, harm, impact, need, problem, state, stress, support

Profitable + business, company, market, product, use, year

Public + access, attention, building, concern, debate, education, enterprise, eye, fund, health, holiday, image, interest, money, perception, policy, pressure, sector, servant, service, spending, transport

Quick + action, buck, decision, learner, reaction, response, sale, succession, wit, word

Rapid + change, decline, development, expansion, growth, improvement, increase, pace, rate, reaction, response, rise, spread, transit

Rare + animal, book, case, event, example, exception, instance, moment, occasion, occurrence, opportunity, sight, species

Regular + basis, check, customer, exercise, interval, job, service, use, visitor, work