The main purpose is to save a state of an object, In order to restore the object at an appropriate time, I think it is more vivid to call the backup mode. Generally speaking, assuming that there are various attributes in the original class A and A, A can decide the attributes to be backed up, memo class B is used to store some internal states of A, and class C is used to store memos and can only store, not modify and other operations. Make a picture to analyze it:1949年，上海解放前夕。物价飞涨，民不聊生，人们经受着失业、饥饿和白色恐怖的威胁，学生们也在为自己的生活和减免费担忧。上海某弄堂中学的学生，正在注视着学校减免费的名单。结果，依靠黑暗势力的阿飞学生吴关根等得到了全免，而家境贫寒的学生江大成和吕小可却只免了三分之一。不公平的待遇引起了学生们的愤懑和不平，失学的危机笼罩在学生们的头上：《新少年报》通讯员江大成为了解决学费问题，把同学们召集起来，与学校展开了斗争。阿飞学生吴关根偷听了江大成的讲话后，密告给反动的朱校长，朱校长在伪警察局吴督察的密令下，借口江大成出售《新少年报》，把他开除。江大成在党的地下工作者杨明老师的诱导下走上了革命道路。在江大成的影响下，吕小可、陈玉珍、何贵生都参加了地下少先队。他们把被查封的《新少年报》改为墙报在学校出版，把革命的道理传播给同学们。地下少先队的孩子们机智勇敢地开展了对敌斗争，他们在深夜来到朱校长的办公室，收听新华社广播，把解放军胜利渡江的消息印成传单，以卖报做掩护，秘密发传单，贴标语，唤起人们的斗志。他们发出的警告信像炸弹一样震动着敌人，使特务吴督察和朱校长惊慌失措，地下少先队的孩子们引起了他们的怀疑。在紧要的关头，杨明老师挺身而出，掩护了孩子们，但却引起了敌人对他的怀疑。江大成得到敌人要逮捕杨明老师的消息，正要去报告，杨明却来到他家，布置迎接上海解放的任务。特务突然赶来追捕杨明，在孩子们的掩护下，杨明安全转移。终于，他们迎来了上海的解放。在雄壮的少先队队歌声中，一批新队员正在举行入队仪式。当江大成为小伙伴带上红领巾时，他的心情无比激动，他决心永远跟着共产党走，做共产主义事业的接班人。红椒性子烈，在这样的环境里生活，也能应对容易些。Since the 1920s, the influx of Western journalists into China has been like crucian carp crossing the river, but as far as the social status at that time is concerned, no one can expect Aban to match it. Aban is naturally competitive and can't compete for emergencies in the front line, but his real advantage lies in his extensive upper-level relations. The top level of the Chinese government and the top level of Japan, the United States, Britain, the Soviet Union and other countries in China are full of his personal friends. At the beginning, the national government wanted to expel him from the country, but later, all four families took him as their guest of honor. Japan attaches more importance to the fact that the top leaders of various factions and departments in civil and military affairs are eager to break through his threshold. The Soviet Union was also interesting. While setting off a wave of criticism of Aban, it sent an ambassador to talk with him in secret and entrusted him with conveying high-level meanings. As for the United States and Britain, it goes without saying. The importance of Aban lies in the fact that his role has completely gone beyond that of a mere reporter. To the U.S. Government, he is an unpaid senior intelligence agent, providing top secret information free of charge, weighing more than any official spy. To the rest of the governments, he is a supernumerary U.S. Diplomat, and his role is often beyond the reach of U.S. Ambassadors. Therefore, between Japan and the United States, between China and the United States, and between the United States and the United States, he has to send messages frequently. As for the infighting among various countries, they should also reveal their secrets to him so that they can be published in the New York Times and confuse each other. For example, before Japan officially joined the Axis, because of the confrontation between the two factions at the highest level, some people secretly told each other the news, which made him get a global super scoop for no reason. All this, of course, depends on the golden signboard of the New York Times and its inexhaustible resources.講述四個高中生賴皮、群群、恬與喳喳，在一間廢墟裡直播，打算抓鬼衝人氣，好藉此賺錢，然而，他們在裝神弄鬼之間，卻真的碰上異度世界的鬼……Use-t to specify the table to operate on, and the-P option to specify the chain to modify. In the above example,-P FORWARD DROP means to change the default policy of FORWRD chains in the table to DROP.Liu Spruce, an associate professor at Peking University, made statistics: In the 1980s, 30% of Peking University students came from poor families. In the 1990s, the proportion of poor families began to decline gradually. After 2000, the proportion of poor families was only over 10%.
