题干

请你用图(1)的四块拼板,在图(2)中评出图(3),并说一说你的操作过程。

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答案(点此获取答案解析)

将图(1)中左上角的一块绕某一点顺时针旋转90°拼在图(2)的左上角;将图(1)中右上角的一块绕某一点按逆时针旋转90°拼在图(2)的左下角;将图(1)中左下角的一块绕某一点顺时针(或逆时针)旋转180°拼在图(2)的右下角;最后将图(1)中右下角的一块绕某一点逆时针旋转90°拼在图(2)的右上角。

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    Papa's jaw dropped when Mama told him that Sister had cheated on her final exams—not to succeed but to fail. “It's unbelievable!” he said. “Sister has always been so proud of her good grades!”

    “Yes, she has,” said Mama. “But it's not unbelievable. It just shows how badly she wanted off the swimming team.”

    “Wanted off the swimming team?” said Papa. “She never said anything about that to me.”

    “Of course she didn't,” said Mama. “She was afraid you'd blow your top. You already had her getting a swimming scholarship to college and winning gold medals at the Olympics. Can you imagine how much pressure she must have felt? For her, being on the team couldn't have been much fun.”

    “Oh, my god!” Papa said, clapping a hand to his forehead. “I've been so stupid! I just thought she'd want to be a champion swimmer because she's so good at it.”

    “It's like anything else, dear,” said Mama. “No matter how good at it you are, if it stops being fun, you won't want to do it anymore.”

    Papa put his head in his hands.

    “She must be really mad at me,” he mumbled. “Maybe I should say sorry to her.”

    Sister's footsteps could be heard on the stairs. She came into the kitchen and looked hopefully up at her parents.

    “Honey,” said Mama with a smile, “your papa and I have decided that there's no reason for you to be on the swimming team if you don't want to.”

    Sister's face lit up like a Christmas tree. “Yippee!” she cried.

    “And,” added Papa, “there's no need for any more drills. I'm sure you'll bring your grades back up all by yourself.”

    Sister ran to Papa and jumped into his arms. She gave him a big hug. “I'm going to go play cards with Lizzy!” she said. “See you later!”

    From the kitchen window, Mama and Papa watched their daughter run down the sunny road toward Lizzy's house.

    “It's good to see her happy again,” said Mama.

    “It sure is,” Papa agreed. “As for the swimming team, there's always next year.”

    “If?” Mama prompted him.

    “Oh, right,” said Papa. “If she wants to.”

    Mama smiled. “At least you're learning, dear,” she said. She kissed him.

    “Well, you know what they say,” Papa said. “Better late than never.”