1 . Most people can't wait for spring to arrive. It means flowers and warmer weather, all welcome changes from the dark winter days. Now we know that spring is arriving sooner in the Northern Hemisphere   (北半球）than it was in the past, thanks to a study published in Scientific Reports.

For example, Los Angeles may experience spring only a day earlier than it did 10 years ago, but further north, in Seattle or Chicago, spring will arrive four days earlier. If you lived in the Arctic, spring could arrive 16 days earlier than it used to.

To determine how springtime is starting earlier, researchers looked at temperature records and 743 earlier studies over 86 years. These studies were about various biological indicators of spring, including birds migrating, plants flowering and amphibians（两栖动物）sounding their mating calls. Researchers then studied these data to see if they were occurring earlier. The result showed that not only is spring making itself known sooner but it's warmer, too.

Before you go out in a happy springtime hike, spring arriving sooner isn't so good. The livelihood of migratory birds, for instance, may be concerned.

“The food that birds rely on when they move to the north might not be reliable if the beginning of spring at these higher latitudes（维度）is expanded by future warming." said Eric Post. He is a fellow of the John Muir Institute and a polar ecologist.

Animals relying on Arctic sea ice, like polar bears, probably aren't crazy about things warming up sooner, either, because it impacts on their ability to hunt. Spring's early arrival could cause disorder in the delicate balance of various ecosystems~~not to mention how soon you'll need to buy allergy medicine.

1. We learn from the study published in Scientific Reports that.

A．spring comes earliest in Los Angeles

B．Los Angeles is further north than Seattle

C．spring comes 12 days earlier in Arctic than in Chicago

D．the further north a place lies, the sooner spring comes than before

2. Researchers made the discovery mainly by.

A．comparing related data available

B．conducting research and test

C．calculating the exact length of each spring

D．observing animal's behavior all year round

3. What do the last two paragraphs focus on?

A．Concerns over spring's early arrival.

B．Springtime emergence of creatures.

C．Early springtime's impacts on humans.

D．Disorder in the balance of ecosystems.

4. In which section of a magazine can we read this text?

A．Medical Report.	B．Survival Stories.
C．Scientific Discoveries.	D．Natural environment