题目内容：

    For underwater photographer Brian Skerry, there are good days. The sun shines, the water's clear. But most days aren't like that. The whales don't show up, or there are particles (颗粒)in the water, or wind brings the waves, or the sun dips behind a cloud at the worst moment.

A National Geographic photography fellow and the 2017, Rolex National Geographic Explorer of the Year, Skerry free dives — which means no scuba tanks, no equipment except his fins, mask, and camera. Over the past two years he's spent nine weeks off the eastern Caribbean island of Dominica in a 30-Foot boat running after sperm whales around their warm-water habitat.

Sperm whales are intelligent, and mad, escaping to ocean depths when pursued. Still, their ranks have been thinned by whaling, overfishing, and other contact with humans, to the point that the world's conservationists assess them as either vulnerable or endangered. Skerry wants his photos to inform the scientific research and education efforts that will bring whales more attention and potentially some relief. “I feel a sense of responsibility and urgency to make people care about the marine giants,” he says. “I want to give them, for lack of a better word, some humanity.”

Scientists know sperm whales as the ocean's largest toothed animals that kills other animals. They have the biggest brains of any known animal, can weigh up to 45 tons, and have been observed displaying humanlike qualities, such as curiosity and playfulness. But despite their size and their expressiveness, sperm whales remain one of the ocean's biggest mysteries. Do they share complex ideas?

1.What is "free dives"?

A.Diving without charge. B.Diving without sponsors.

C.Diving with little equipment. D.Diving with few regulations.

2.What does the underlined word "vulnerable" probably mean?

A.Easily attacked. B.Strongly built.

C.Desperately driven. D.Distantly removed.

3.What can we learn about the sperm whales from the text?

A.Sperm whales are the largest fish in the sea.

B.Sperm whales are as clever as the human being.

C.Sperm whales enjoy being photographed by photographers.

D.Sperm whales' population has declined due to illegal fishing.

4.Where is the text probably taken from?

A.Technology magazine. B.Tourism advertisement.

C.National geography. D.Entertainment report.