This past winter's negative phase of the Arctic Oscillation transported old ice (four, five, and more years old) from an area north of the Canadian Archipelago.

去年冬天北极这种负向振荡从加拿大群岛北部地区运来多年老海冰(四，五年或更多年的老海冰)。

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There are four categories of figure skating: men's singles,women's singles, pairs,and ice dancing.

VOA: special.2010.02.10

But the volume of the Martian north polar cap is less than half that of the Greenland ice cap, and about four percent of the Antarctic ice sheet.

BBC: By BBC News Online Science Editor Dr David Whitehouse

Belcher got stuck in the Canadian ice and abandoned four of his five ships.

FORBES: The Great Northern Beer Adventure

This study selected four ICE-based vehicles, and modeled BEVs based on the specifications of each of these vehicles.

FORBES: Electric Cars May Accelerate Global Warming