下列图标中属于消防安伞标志的是（）

某物质能与水反应，将少量该物质加到饱和石灰水中，石灰水变浑浊，则下列说法正确的是

阅读下列材料，回答问题：
材料一   “治世不一道，便国不法古” ——摘自人教版《中国历史》七年级上册
材料二 

材料三   《史记》记载，守旧贵族由于利益受损，他们和太子串通一气，就诽谤商鞅。秦孝公死后，太子即位，商鞅失去了支持，被诬陷为“谋反”，“车裂”而死。
（1）材料一这句话是谁说的？ 表明他什么思想？
（2）材料二所反映的内容与他的哪一项变法措施相对应？
（3）从材料三之中，可以看出改革遭遇到最大的困难是什么？
（4）结合所学知识，说说商鞅变法的历史影响。

(A)

    China Youth says that more and more girl students have entered colleges to study in the recent few years. As we know, once the number of boys was larger than that of girls, and boys did much better than girls in our country for a long time. Now, things have changed a lot.

    In recent years, the proportion of girl students is growing fast. In 1998, about 39.7% of college students were girls. In 2000, it was 41.07% and in 2001, the number was 42.14%.

    There are several reasons for this.

    Firstly, there is little difference between boys and girls in their intelligence(智力). That's to say, girls are as clever as boys. And boys have more interests than girls, so they may not always do well in their study.

    Secondly, girls are more careful than boys. They work harder at school and they do better in all exams. Another reason is that with the development of society, people pay more and more attention to girls' education.