把一只实心铁球放入一满杯水中，溢出水的质量为m₁，放入满杯酒精中溢出酒精的质量为m₂，(ρ_水＞ρ_酒精)(       )

恩格斯说过，“正像在18世纪的法国一样，在19世纪的德国，哲学革命也作了政治崩溃的前导。”这句话表明，真正的哲学作为一种巨大的精神力量，是社会变革的先导。下列各项中能够体现哲学思想上述作用的典型事件是（    ）

①战国时期百家争鸣的思想繁荣局面催生了新的封建制度

②“罢黜百家，独尊儒术”成为中国封建社会长期稳定的思想基础

③18世纪资产阶级启蒙运动迎来了法国资产阶级大革命

④马克思主义哲学开辟了无产阶级和全人类解放事业的新时代

    We each have a memory（记忆力）. That's why we can still remember things after a long time. Some people have very good memories and they can easily learn many things in a short time, but some people can only remember things when they say or do them again and again. Many of the great men of the world have got surprising memories.

    A good memory is a great help in learning a language. Everybody learns his mother language when he is a small child. He hears the sounds, remembers them and then he learns to speak. Some children are living with their parents in foreign countries. They can learn two languages as easily as one because they hear, remember and speak two languages every day. In school it is not so easy to learn a foreign language because the students have so little time for it, and they are busy with other subjects, too.

    But your memory will become better and better when you do more and more exercises.