Ⅰ.阅读理解
A
Biologist Robert Pitman and his colleagues tracked orcas，or killer whales，and humpback whales off the coast of Western Austra lia.To research further，the scientists attached a tracker to a female orca，which allowed them to use satellites to monitor her movements.They followed her for six days.During that time，the orca attacked eight young humpback whales.During the seven attacks，the orca killed the humpback whale calf (幼兽) on three occasions.
But the story doesn't end there.Humpback whales themselves are popularly thought to be large but generally，passive creatures.Pitman's study findings may let people think otherwise.
When chased by orcas，humpback whales are known to try to outswim orcas.They are thought to do this at high speed so that the orcas can't keep up.On some occasions，the humpback whales sought out protection.They swam to shallow water，nearby reefs，or even under the researchers' boats.These ways often reduced the attack.But at other times，the humpback whales decided to stay and fight.
