An obstacle can be to travel.Logical formLearned from18 sentences. (Travel advisory) may undergo a lifting.Logical formLearned from18 sentences. Travel can be known.Logical formLearned from18 sentences. (Air travel) may undergo a disruption.Logical formLearned from18 sentences. A (travel reservation system) may pertain-to a scientist.Logical formLearned from18 sentences. A person may work at a (travel agency).Logical formLearned from18 sentences. Travel can be tough.Logical formLearned from18 sentences. Travel can be by some officials.Logical formLearned from18 sentences. A day can be for travel.Logical formLearned from18 sentences. An (air travel) can be asian.Logical formLearned from18 sentences. Volcanic ash may disrupt (air travel).Logical formLearned from18 sentences. (Travel patterns) may change.Logical formLearned from18 sentences. Persons may advise against travel to a country.Logical formLearned from18 sentences. Travel can be to islands.Logical formLearned from18 sentences. A (travel advisory) can be against a world-city.Logical formLearned from18 sentences.