One sunny Sunday morning, Alex and Emma were playing football in the park. Their dad was sitting on a chair, reading a newspaper.

    Then Emma stopped and walked to Alex. “It's too hot,” she told him. “I think I need a sun hat.” “Me too!” Alex agreed.

    Emma looked at her dad's newspaper and said, “I have an idea.” She asked Dad for two sheets of newspaper and made each of them into a hat. Then she put one on Alex's head and the other on hers. “The hat is great!” Alex said.

    They sat down next to Dad and watched everyone in the park. Then the wind began to blow. Some people started flying kites. “I wish I had a kite,” Alex said. “Or a plane!” Emma said. She took off their hats and made them into two planes.

    They played with their planes until they heard thunder (雷声). “Oh, it's time to go home now,” Emma said. “Or all of us will get wet even if I make each of us a paper umbrella!”

人体免疫有三道防线,在这三道防线中,属于非特异性免疫的是        (　　)

以洋务运动为起点，中国近代化的探索，不仅给中国的经济带来了变化，也改变了中国人民的社会生活。在近代史上，交通通 讯工具开始在近代中国出现。火车、轮船等交通工具的应用，有线电报的传入，照相和电影传入中国，新闻报纸、出版机构开始出现，中国社会的生活开始变得丰富 多彩。