Analysis of test questions: According to historical facts, ① "Down with the great powers except the warlords" should happen after the "Second National Congress", ② "Stop the civil war and unite against Japan" happened on the eve of the start of the all-round war of resistance; (3) "Fighting for state power outside and punishing state thieves inside" occurred in the May 4th period; (4) "Long live the China people and country" should appear after 1949. Therefore, you should choose item B.

Comments: This title is arranged multiple-choice questions (sequential multiple-choice questions). According to the requirements of the topic, some historical events or phenomena are arranged in a certain order, especially in time 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 you can determine the earliest or last one, even if you don't know the individual time, you may choose the correct answer or greatly improve the hit rate. Whether we can grasp the concept of time accurately and firmly is the key to answer this kind of question.