Across Earth, life is a dance filled with the push and pull of many partners. But in the Arctic, living things have fewer choices. The harsh1 climate reduces the dance of life to2 close partnerships--a dance whose push and pull means life or death.
When the Arctic spring begins in April, the sun and ice begin their yearly dance. The sun takes the lead, and the Arctic waters stir with life. When the vast3 ice sheets crack,4 sunlight pours into the icy waters, and algae cover the edges of the ice. Tiny shrimp come to eat the algae, and millions of cod come for the shrimp.
Like many other Arctic animals, ringed seals feed on cod. And being mammals, seals must leave the water to breathe and sleep. At these times, seals must face the danger of waiting polar bears.
Masters of the Arctic, polar bears are hidden from their prey by their white fur and can smell seals from a kilometer away. Nevertheless, polar bears only catch one in twenty seals. This dance requires patience5.
1. harsh adj. not easy to bear 严厉的
The dry, hot environment of this desert is too harsh to support much life.
2. reduce...to... v. phr. to break sth. down to its basic parts 把……简化为； 把……归结成
Days of heavy rain reduced the farmer's fields to a huge sea of mud.
3. vast adj. extremely large; spread out over a very large area 巨大的；广大的
Because the earth's oceans are so vast, much of the seafloor is unexplored.
4. crack v. to break or separate along a line 裂开；破裂
While I was driving today, a rock flew up and cracked the window of my car.
5. patience n. the ability to wait a long time for sth. 耐心
Fishing takes lots of patience because you have to wait for the fish to bite.