1. When the captain found the ship was rapidly sinking£¬he ordered his men to send out a ________ for help.

A. signal                               B. sign

C. symbol                               D. signature

2. Usually the Player of the Year title is given to a big name from the best team.But this time there is a(n) ______.

A. break                                B. improvement

C. exception                            D. tradition

3. Scientists have made a major ________ in the treatment of cancer.

A. barrier    B. breakthrough

C. companion    D. concern