作文：

      罗曼·罗兰说：“最可怕的敌人，就是没有坚强的信念。”的确，信念支持着人生。信念是呼吸的空气，信念是沙漠中旅人的饮水，信念是我们心中的太阳。信念坚定的人，为了它无怨无悔地工作，尽心尽力的奋斗，甚至甘愿洒下最后一滴鲜血。正如丁玲说：人，只要有一种信念，有所追求，什么苦都能忍受，什么环境也能适应。
      请以“信念”为话题写一篇文章。
      要求：①立意自定；②文体自选；③题目自拟；④不少于500字。

一株绿色开花植物形成果实和种子，一般必须完成两个重要的生理活动，它们是____和____．

如图甲和乙表示细胞结构，丙表示某种生理过程图，请据图分析回答：

    No one knows what our life will be like in the future. Here are some children's  1.

    Cindy: In the future, people will have more holidays. They2a lot of time to travel around the world. Maybe some families will go to the moon  3 their holidays.

    Gary: I think the earth will be more crowded and polluted. Maybe some people will 4  their houses on other planets.

    Sarah: Students in the future won't need to go to school and they will study at home. What will happen  5 students have problems with a subject? They will  6with a teacher through videoconferencing (视频会议).

    Peter: In the future, people will speak fewer languages. Maybe there will be  7one language in the world. And it will be much  8 for people to talk with each other.

    Laura: Robots will play an important role in our life. 9will help humans do all kinds of work.

    These predictions may seem impossible today, but I10 they will come true one day because we never know what will happen in the future.

下列图形经过折叠不能围成棱柱的是（   ）