分母不同的分数不能直接相加减。

1975年湖北云梦睡虎地秦墓中出土了大量简牍，其中《行书律》规定：“行命书及书署急者，辄行之；不急者，日毕，不敢留。留者以律论之。”还规定“行传书，受书，必书其起及到日月夙暮……”根据这些内容，我们可以推断出  
①秦朝法律严明，且分类很细           ②秦朝时儒家经典《书》在民间大量流传 
③秦朝时邮驿通信制度逐步规范化       ④秦朝以此保证政令畅达和巩固统治

   The best way of learning a language is using it. The best way of learning English is talking in English as much as possible. Sometimes you'll get your words mixed up(混合) and people will not understand you. Sometimes people will say things too quickly and you can' t understand them. But if you keep your sense of humor(幽默感)，you can always have a good laugh at the mistakes you make. Don't be unhappy if people seem to be laughing at your mistakes. It's better for people to laugh at your mistakes than to be angry with you，because they don't understand what you are saying. The most important thing for learning English is："Don't be afraid of making mistakes because everyone makes mistakes."

阅读下面甲、乙两文，完成1-4题。

【甲】北山愚公者，年且九十，面山而居。惩山北之塞，出入之迂也，聚室而谋曰：“吾与汝毕力平险，指通豫南，达于汉阴，可乎？”杂然相许。其妻献疑曰：“以君之力，曾不能损魁父之丘，如太行、王屋何？且焉置土石？”杂曰：“投诸渤海之尾，隐土之北。”遂率子孙荷担者三夫，叩石垦壤，箕畚运于渤海之尾。邻人京城氏之孀妻有遗男，始龀，跳往助之。寒暑易节，始一反焉。

河曲智叟笑而止之曰：“甚矣，汝之不惠！以残年余力，曾不能毁山之一毛，其如土石何？”北山愚公长息曰：“汝心之固，固不可彻，曾不若孀妻弱子。虽我之死，有子存焉；子又生孙，孙又生子；子又有子，子又有孙；子子孙孙无穷匮也，而山不加增，何苦而不平？”河曲智叟亡以应。

【乙】鲁公治①园，欲凿池，父曰：“无地置土。”公遂止。或曰：“土可垒山。”公善之，欲行。妻曰：“不畏小儿女颠踬②耶？”公复止。或曰：“筑径通之，设栏护之，又何忧焉？”公从之，又欲行。家人有止之者曰：“园成必添仆妇，下房不足，甚可虑也。”公犹夷③不能决，事又寝④。

【注】①治：修建。②颠踬：被东西绊倒。③犹夷：迟疑不决的样子。④寝：停止。

《宣言》认为：“国民党之民权主义，于间接民权之外，复行直接民权，即为国民者不但有选举权，具兼有创制、复决、罢官诸权。……国民党之民权主义，为一般平民所共有，非少数人所得而私。”下列对该《宣言》理解和认识，不正确的是（    ）