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It’s late autumn in the Arctic Ocean （大西洋） . The water is covered with ice. It’s difficult for the white whales to breathe, so they come up to find openings in the ice to get enough air. As the winter is coming, they know it’s time to leave.
A group of about a hundred white whales swim south toward the Bering Sea. Halfway through their journey, their enemy, an orca（虎鲸）is swimming toward the white whales. With the help of large ice floes（浮冰）, the white whales swim faster than the orca. This gives the white whales time to swim away.
After a few more days of swimming, they arrive at the Bering Sea. The white whales will rest, hunt, and play here until April, then they’ll swim back to the Arctic Ocean.
1．Why do the white whales come up to find openings in the ice?| A．To get enough air. | B．To get enough food | C．To keep warm. |
| A．Their teeth. | B．Large ice floes. | C．Brave fights. |
| A．February | B．March | C．April |
| A．How Can White Whales Live in Summer? |
| B．White Whales Are on the Move. |
| C．White Whales Are in Great Danger. |
同类型试题
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
