Oh, my God! Is this your room? The furniture here remains _____ with such thick dust!

A. covered         B. covering           C. to cover       D. be covering

---- How did you know the surprising news?????????????????

?? ---- I happened ____ the event then.

A. to cover????? B. to be covering???? C. covering?? D. to have covered?

Some of the planet’s most precious animals and plants are disappearing, according to the World Conservation Union (IUCN). The group, based in Switzerland, works with governments and experts to protect threatened species. On September 12, the IUCN released its Red List, a list of species at greatest risk of extinction.
The list includes 41,415 animals and plants. The IUCN says that habitat destruction, hunting and other causes threaten one in four mammals, one in eight birds and one in three amphibians(两栖动物).
Who is to blame?
Scientists believe that 99 percent of threatened species are at risk because of human activity. “We are losing animals and plants at a high rate,” says Julia Marton-LefEevre, director general of the IUCN. “We need to change our behavior.” Warmer oceans and over-fishing are changing sea life. This year for the first time corals(珊瑚) made their appearance on the list. The gharial, a crocodile living in India and Nepal, has lost almost 60 percent of its population in the last 10 years. It is a victim（受害者）of habitat destruction.
Still, the news is not all bad. Thanks to efforts made to protect it, the Mauritius echo parakeet, a bird once endangered, has seen an increase in its population. “This shows that protection methods can work,” says Marton-LefEevre. “That’s the message we want to send to young people.”
In China the new reserve（保护区）itself is part of green efforts that have seen more than 2,400 nature reserves of various kinds being set up, covering more than 15 percent of the nation's land area, official figures showed.
"The country's natural resources(资源) have benefited from conservation," said Lei Guangchun, director of the nature reserve department of Beijing Forestry University. "It is a big increase nowadays compared with other countries." Lei said.
The total areas of China’s natural reserves have covered 1.38 million km2, which accounts for 15.4% of China’s area, higher than both the world average（平均水平） of 11% and the rate in most developed countries.
Li Zhong, an official in charge of the nature reserves office with the State Forestry Administration, thought it was important to increase investment（投资） in such reserves at all levels.
【小题1】What do we know about the IUCN?

  Some of the planet’s most precious animals and plants are disappearing, according to the World Conservation Union (IUCN). The group, based in Switzerland, works with governments and experts to protect threatened species. On September 12, the IUCN released its Red List, a list of species at greatest risk of extinction.
The list includes 41,415 animals and plants. The IUCN says that habitat destruction, hunting and other causes threaten one in four mammals, one in eight birds and one in three amphibians(两栖动物).
Who is to blame?
Scientists believe that 99 percent of threatened species are at risk because of human activity. “We are losing animals and plants at a high rate,” says Julia Marton-LefEevre, director general of the IUCN. “We need to change our behavior.” Warmer oceans and over-fishing are changing sea life. This year for the first time corals(珊瑚) made their appearance on the list. The gharial, a crocodile living in India and Nepal, has lost almost 60 percent of its population in the last 10 years. It is a victim（受害者）of habitat destruction.
Still, the news is not all bad. Thanks to efforts made to protect it, the Mauritius echo parakeet, a bird once endangered, has seen an increase in its population. “This shows that protection methods can work,” says Marton-LefEevre. “That’s the message we want to send to young people.”
In China the new reserve（保护区）itself is part of green efforts that have seen more than 2,400 nature reserves of various kinds being set up, covering more than 15 percent of the nation’s land area, official figures showed.
"The country’s natural resources(资源) have benefited from conservation," said Lei Guangchun, director of the nature reserve department of Beijing Forestry University. "It is a big increase nowadays compared with other countries." Lei said.
The total areas of China’s natural reserves have covered 1.38 million km2, which accounts for 15.4% of China’s area, higher than both the world average（平均水平） of 11% and the rate in most developed countries.
Li Zhong, an official in charge of the nature reserves office with the State Forestry Administration, thought it was important to increase investment（投资） in such reserves at all levels.
【小题1】What do we know about the IUCN?

----- How did you know the surprising news?

----- I happened _______ the event then.

A．to cover          B．to be covering      C．covering          D．to have covered