通常用的蛋白质测试方法“凯氏定氮法”是通过测出含氮量来估算蛋白质含量，其含氮量一般不超过30%，而三聚氰胺的含氮量为66%左右，因此三聚氰胺也被人称为“蛋白精”．人和动物长期摄入三聚氰胺会造成生殖泌尿系统的损害、膀胱肾部结石，最终导致肾衰竭而死亡．以鼠为实验材料，请你设计实验，验证三聚氰胺对小鼠的危害性．

（1）实验步骤：

步骤1：选取生长状况相同的小鼠若干只，____ ．

步骤2：设置对照实验：甲组小鼠____ ，乙组小鼠____ ，作为对照．

步骤3：____ ．

步骤4：每天检测小鼠的健康状况，统计各组小鼠死亡的数目．

（2）实验结果预测____ ．

（3）实验结论：____ ．

下列物质中含有磷元素的是（　　）

阅读下面短文，掌握其大意，然后从各小题所给的四个选项中选出最佳选项。

    One thorn(刺) of experience is worth many times of warning.

    Ralph Wick was seven years old. In most things he was a fine boy, but he would cry from time to time. When he could not have what he wanted, he would 1for it. If he was told that it would hurt him, and he could not 2 it, he would also cry.

    One day, he went with his mother into the 3. The sun shone. The grass was cut. The flowers were starting to come out.

    Ralph thought he was, for once, a good boy. A 4 was on his face. He wished to do as he was told. Ralph helped his mother with the farm work and he was very happy.

    “Now you must be tired and 5,” said his mother. “Have a good rest here and eat some cookies. I will get a beautiful red rose for you.” So his mother brought the red flower to him. When he saw his mother still had a white rose in her hand, Ralph 6 it.

    “No, my dear.” said his mother. “See how many thorns it has. You must not touch it, or you would be sure to hurt your 7.” When Ralph found that he could not have the white rose, he began to cry, and 8 took it away. But he was soon very sorry. The thorns hurt his hand. It was so 9 that he could not use it for some time.

    Ralph would never 10 this. From then on, when he wanted what he should not have, his mother would point to his hand which had been hurt before. He at last learned to do as he was told.