A
It was a lifesaving task as thrilling as any in the months-long battle against the wildfires that have torn through the Australian bush. But instead of a race to save humans or animals, a specialized team of Australian firefighters was bent on saving invaluable plant life: hidden groves (树林) of the Wollemi pine, a prehistoric tree species.
Wollemi pines peaked in abundance 34 million to 65 million years ago, before a steady decline. Today, only 200 of the trees exist in their natural environment. The trees are so rare that they were thought to die out until 1994. That’s the year when David Noble, an officer with the New South Wales National Parks and Wildlife Service, came across a grove of large trees he didn’t recognize.
Noble brought back a few branches and showed them to other biologists and botanists. A month later, Noble returned to the grove with some scientists. It was then that they realized what they had found: “a prehistoric tree species that has outlived the dinosaurs.” the American Scientist explains. So when Australia’s wildfires started burning toward Wollemi National Park in recent weeks, firefighters from the parks and wildlife service put a carefully planned operation into action.
Large air tankers dropped fire retardant (阻燃剂) around the pines. Firefighters set up an irrigation (灌溉) system around the trees to keep them wet. “If the fire did go through, we wanted it to be a cool burn as opposed to a hot burn to give them the best chance of survival,” Kean said. The fire did sweep through the groves where these trees have somehow survived for millions of years. For a few days, the smoke was so thick that it wasn’t clear whether the plan had worked. At last the smoke eased off. A few trees had been burned by the flames, and two died. But the efforts had paid off. “Finally,” Kean said, “we were able to get in there and see that, thank goodness, the trees were saved.”
20.What do we know about Wollemi pines?
A.Scientists searched for them in the wild.
B.They used to grow in parts of Australia.
C.There were a considerable number of them long ago.
D.Firefighters and biologists cooperated to keep them alive.
21.Which of the following can best replace the underlined word “outlived” in Paragraph 3?
A.been superior to. B.been related to.
C.died earlier than. D.existed longer than.
22.What can be learned from the last paragraph?
A.It was cool to drop retardant over the fire.
B.It wasn’t clear whether the trees were saved.
C.It helped the trees survive to keep them wet.
D.It worked best for the trees to keep a hot burn.
23.What is the passage mainly about?
A.An investigation into Wollemi pines.
B.A hard-won battle against the wildfires.
C.Constructing a firefighting system for the trees.
D.Saving world’s rare pine species from wildfires.
