A、He keeps the egg warm. B、He gathers food for the female. C、He builds a nest for the egg. D、He defends the colony. A选项中的He，keep

W: Let’s go into the penguin house.
M: Wonderful! I read that they’ve added a couple of emperor penguins from Antarctica.
W: I was hoping to stay in the warmer section. You know, they have some penguins here from the Galapagos Islands — and that’s practically on the equator.
M: But the emperor penguin’s huge! It’s a lot bigger than the Galapagos penguin. In fact, it’s bigger than all the other penguins — almost four feet high.
W: Imagine a bird that size flying through the air.
M: Penguins don’t actually fly.
W: I know that. They are just kind of waddle.
M: They swim, too. Even though they’re feathered, their wings are more like flippers — they work like paddles in the water.
W: I thought they were land animals.
M: They lay their eggs on land. They make their nests in these enormous colonies called rookeries. See, the emperor penguin has this interesting nesting habit. The female bird leaves the ocean at the beginning of autumn. She lays an egg on the ice and then immediately returns to the water.
W: What happens to the egg?
M: The male rolls it onto his feet and then covers it with the lower part of his belly.
W: Then what?
M: For two whole months, during the worst part of the winter, he huddles together with other male penguins to keep the eggs warm.
W: So the female brings him food?
M: No. See, the penguin can fast for up to four months. The female comes back after the chick hatches. When she does, the male goes out to sea to get food for himself and the chick.
Questions 19 to 22 are based on the conversation you have just heard.
19. Why does the man want to visit the penguin house?
20. What is unique about the emperor penguin?
21. What does the man say about the wings of the penguin?
22. What does the man say about the male penguin?