1 . Noise pollution has a long-term effect on tree populations that may persist even after the sources of noise are removed, according to research published Wednesday.

Man-made noise from industry and the building of infrastructure such as roads and pipelines has increased greatly since the middle of last century. While previous research has documented the short-term effect noise has on tree populations as it scares off pollinators (传粉者) such as insects and animals, few studies have covered the long-term effect.

Researchers in the United States looked at tree populations in New Mexico that had been “hearing”a high level of man-made noise for 15 years. They found 75 percent fewer pinyon pine seedlings (矮松苗) in noisy places than quiet ones.

Then they looked at other places in New Mexico, where sources of noise had recently been added and then removed, and examined how populations recovered. The team assumed that populations of the trees — in this case pinyon seedlings — would recover as the pollinators would return to the places once the noise had disappeared. Instead, they found a long-term drop in seedling numbers as the birds refused to revisit the places.

“The effects of human noise pollution are growing into these woodland communities,” said Clinton Francis, lead researcher from California Polytechnic State University. “What we’re seeing is that removal of the noise doesn’t necessarily immediately result in a recovery of ecological function.”

Jennifer Phillips, co-author of the research, said the findings showed how the effect of noise pollution could put pollinators off even after the noise is removed. “Animals like the birds that are sensitive to noise learn to avoid particular areas.” said Phillips. “It may take time for animals to come back to pollinate trees in these previously noisy areas, and we don’t know how long that might take.”

As governments continue to face growing evidence of the damage to nature caused by urbanization (城市化), Phillips held that the influence of noise pollution should also be factored into planning decisions.

1. What does the underlined word “persist” mean in paragraph 1?

A．Recover.

B．Decrease.

C．Last.

D．Disappear.

2. How did Clinton Franci’s team carry out the research?

A．By studying cases in New Mexico.

B．By challenging the previous research.

C．By recording the routines of pollinators.

D．By following the sources of noise pollution.

3. Which of the following would Phillips most probably agree with?

A．Noise pollution kills large numbers of birds.

B．Governments should take measures to remove noise.

C．Ecological recovery contributes to the removal of noise.

D．It’s hard to tell when birds will revisit previously noisy places.

4. What does the text mainly talk about?

A．Removing noise enables plants to grow better.

B．Pollinators play a role in increasing plant population.

C．Noise pollution has long-term effects on plant populations.

D．Man-made noise does great harm to woodland communities.