A、On 5 June. B、On 20 March. C、On 15 July. D、On 26 April. A

World Environment Day was established by the United Nations General Assembly in 1972 to mark the opening of the Stockholm Conference on the Human Environment. World Environment Day can be celebrated in many ways, including street rallies, bicycles parades, green concerts, essay and poster competitions in schools, tree planting, recycling efforts, clean-up campaigns and much more.
    Heads of State, Prime Ministers and Ministers of Environment deliver statements and commit themselves to care for the Earth. World Environment Day, commemorated each year on 5 June is one of the principal vehicles through which the United Nations stimulates worldwide awareness of the environment and enhances political attention and action. The World Environment Day theme selected for 2004 is Wanted! Seas and Oceans—Dead or Alive? The theme asks that we make a choice as to how we want to treat the Earth’s seas and oceans. It also calls on each and every one of us to act. Do we want to keep seas and oceans healthy and alive or polluted and dead?