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

Merit + attention, consideration, mention

Nurture + child, hatred, ideal, relationship, talent

Obey + command, instruction, law, obligation, order, parent, rule

Obtain + advice, benefit, consent, degree, detail, evidence, information, permission, result, service, solution

Offer + advice, assistance, chance, choice, discount, explanation, help, job, money, opportunity, resistance, service, support

Offset + advantage, benefit, cost, decline, demand, effect, gain, growth, impact, increase, loss, problem, profit, reduction, revenue, sale, tax

Oppose + change, idea, law, move, plan, policy, proposal, view

Overcome + barrier, challenge, crisis, difficulty, fear, hurdle, limitation, obstacle, odds, opposition, prejudice, problem, resistance, shyness

Overtook + achievement, fact, factor, importance, link, need, point, premise, self-esteem