听力原文： The association representing British airline pilots says that there is an urgen

t need to raise levels of air safety throughout the world. In the statement the association, known as Boper, warns that unless air safety improves travelers face a perilous future. The association also said that the standard of training must be raised among fly crews and air traffic controllers as the sky has become ever more crowded.

The news item is mainly about______.

A．air traffic problems.

B．safety improvement.

C．the number of flights.

D．flight training courses.