单项选择题A．It uses nuclear energy.B．It rests on a cushion of professional air.C．It flies over magnetically activated tracks.D．It uses a device similar to a jet engine.

单项选择题A．To learn how to prevent a bone disease.B．To understand differences between bone tissue and other tissue.C．To find out how specialized bone cells have evolved.D．To create artificial bone tissue.

单项选择题A．A stormy ocean.B．Calm water.C．Golden sand.D．Little waves.

填空题independently

单项选择题A．To see films.B．To read books in the library.C．To attend lectures.D．To visit the Association.