The slogan of different times is

Analysis of test questions: According to historical facts, ① "Down with foreign powers, except warlords" should take place after the Second National Congress, ② "Stop the civil war and unite against Japan" took place on the eve of the start of all-round War of Resistance against Japanese Aggression; (3) "Fighting for political power from outside, punishing national thieves from inside" occurred during the May 4th Movement; (4) "Long live the people and country of China" should appear after 1949. Therefore, you should choose item B.

Comments: This question is arranged multiple-choice questions (sequential multiple-choice questions). According to the requirements of the topic, arrange some historical events or phenomena in a certain order, especially in chronological order. There are two forms: serial number and non-serial number. To solve this kind of multiple-choice questions, we can adopt the method of beginning and ending (judging from the beginning or the end), that is, first determine the options that do not meet the requirements of the stem. If we can determine the earliest or last one, even if we don't know the personal time, we may choose the correct answer or greatly improve the hit rate. Whether the concept of time can be grasped accurately and firmly is the key to answer this kind of question.