—I'd love to, but I've ________ Linda's invitation to dinner.

As many as 10 of the 17 kinds of penguins (企鹅) may be in danger of disappearing. The number of penguins have decreased (减少) by 30% since 1987.

Penguins are black and white birds that live in the southern part of the world. They are common in South America, New Zealand, Australia and South Africa. Mary live near cold waters. But some live near warm waters in Galapagos Islands. Penguins cannot fly, but they are fine swimmers. Penguins eat fish and krill(磷虾).

The warming of the earth is the decrease in penguin populations. The heating of the air has caused ocean waters to become warmer. Higher water temperatures have reduced the supply of fish and krill. Some years later these birds are completely unable to reproduce(繁殖). Besides, many adult penguins die of hunger.

Widespread(广泛的) fishing, exploration for oil and oil leaks(漏) also make penguins be in danger. Poisonous organisms(生物) in ocean water are another danger. Penguins also have their enemies, including wild dogs, sharks, seals and sea lions.

News about penguins is not all bad, however. Several years ago, oil leaking from a ship hurt 40% of the penguins in South Africa. The penguins became covered with oil. But thousands of people helped clean and treat the birds well. Then they returned the penguins to the wild. Now these South African penguins are reproducing in higher numbers than before the oil leaking.

    In the morning, a grandfather took his grandson to a school. When the boy and his grandfather went into the playground, some children came up.

    "What a funny old man!" one boy said, making a face.

    "Hey, fatty (胖子)," another one shouted.

    The children jeered at them and jumped up and down.

    Without saying a word, the old man took his grandson out of the school gate. "Wonderful! I don't have to go to school!" the boy said.

    "You do, but not this one," his grandfather replied. "I'll find you a school myself." The grandfather took his grandson back to his own house, asked the boy's grandmother to look after him, and then went out to look for a school himself.

    Every time he got to a school, the old man went into a playground, and waited for the children to come out at break time. In some schools the children completely ignored (不理会) the old man, and in others, they made fun of him. When this happened, he would turn sad and go home. Finally, he went into the very small playground of a very small school, and stood tiredly against the wall. The bell rang, and the children got out into the playground.

    "Sir, are you all right? Shall I get you something to drink?" a voice said.

    "We've got a bench in the playground — come and sit down," came another voice.

    Soon a young teacher came out into the playground. The old man greeted him and said, "Finally, I've found my grandson the best school in town."