单项选择题A．Enforcing laws controlling navigation, shipping, immigration and fishing.B．Enforcing laws affecting the privately-owned boats in the U. S.C．Searching for missing boats and rescuing people.D．Training people to be good swimmers along the beach.

单项选择题A．Her subject’s home.B．Her subject’s social status.C．Her subject’s personality.D．Her subject’s role in history.

单项选择题A．Have to buy a special electronic ticket.B．Need an expensive device designed especially for the museum.C．Have to travel a long way to visit the university. [D] Need a computer linked to a telephone.

单项选择题A．A famous photographer.B．Photographic processes in the 1800s.C．Photographic equipment used in the 1800s.D．A new museum.

单项选择题A．Guarding the coasts of the United States.B．Being part of the United States Navy.C．Guiding people along the coast.D．Protecting people from enemy attacks.