单项选择题
A．Most Londoners took Exercise Floodcall calmly. B．Most Londoners were frightened. C．Most Londoners became rather confused. D．Most Londoners complained about the trouble caused by Exercise Floodcall.
A．Pollution of the environment. B．Over-killing by hunters. C．Destruction of their natural homes. D．A new generation of pest killers.
A．Many species have developed a habit of migration. B．Many species have become less sensitive to climate. C．Many new species have come into existence. D．Many species have moved further north.