列关于PDA(个人数字助理)的叙述，错误的是（   ）

下列说法不正确的是（   ）

歌德说：“你若要实现你自己的价值，你就要给社会创造价值。”这句话是说（    ）

某单位有职工750人，其中青年职工350人，中年职工250人，老年职工150人，为了了解该单位职工的健康情况，用分层抽样的方法从中抽取样本 . 若样本中的青年职工为7人，则样本容量为    （  ）

阅读文章，选择正确的答案    Bim is a puppet. He is made of wood. He has arms and legs，and hands and feet. He has black hair and green eyes. There are strings(线)on his arms and legs. There are also strings on his hands and feet.

    Children like to play with Bim. They pull his strings. They move his arms and legs，and his hands and feet. They can not move his eyes or his ears. They can not move his nose or his mouth.
    Pip is a puppet, too. But she is made of cloth. She is a glove puppet. She has arms and hands，but she doesn't have legs or feet. She doesn't have any strings.

    Children like to play with Pip, too. They can put their small hands inside Pip. They can put their fingers in her hands and make them move. Children make Bim and Pip talk to each other. They make them tell each other stories