When there is a problem during operation, such as passenger questions, or need help I do not know. Because the information might not be correct, it cannot be helped. Make some passengers frustrated.
When a problem occurs during operation, such as passenger questions or need help, I do not know about. This information may not be, they can not help. Some passengers were not satisfied.
When the problem between work, such as the passengers ask questions or need help I don't know. Because the data may be incorrect, so can not help. To some passengers caused dissatisfaction.