Millie smiled back! She didn't know how to start jumping with a long rope.
米莉笑着回应！她不知道如何开始用一根长绳子跳。
They both have a long tail, which helps the squirrel to balance when jumping from tree to tree, and the same large eyes, small ears and powerful back legs.
它们都有一条长长的尾巴，帮助松鼠在从一棵树跳到另一棵树时保持平衡，还有同样的大眼睛、小耳朵和有力的后腿。
According to a German professor, the soreness comes from straining your muscles in an uncommon way. For example, jumping on a bicycle for a ride, because you haven't ridden in a long time.
一个德国教授认为，肌肉酸痛是因为肌肉拉伸的方式与平常有所不同，例如，长时间没有骑自行车之后再骑车兜风就会产生肌肉酸痛。
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