In 1905, China was ruled by the Qing Dynasty (1636-1912) whose ruling family was from an area in northeastern China called Manchuria. Some Chinese viewed the rulers of the Qing Dynasty as invaders from outside of what they considered “China.” The power of the Qing Dynasty declined in the mid-1800s when they lost a series of wars to European countries and had to sign treaties that gave those European countries legal power and control of trade with China. The excerpt below was written by a group of Chinese students studying in Japan called the Tongmen Hui (Chinese Alliance Association) led by Sun Yat-sen, the revolutionary leader who would later be the first elected president of China. . . . Since the beginning of China as a nation, we Chinese have governed our own country despite occasional interruptions. When China was occasionally occupied by a foreign race, our ancestors could always in the end drive these foreigners out, restore the fatherland, and preserve China for future generations of Chinese. Today when we raise the righteous standard of revolt in order to expel an alien race [the Manchus] that has been occupying China, we are doing no more than our ancestors have done or expected us to do. Justice is so much on our side that all Chinese, once familiarizing themselves with our stand, will have no doubt about the righteousness of our cause. .

give me the main idea of this in 2 sentence

The main idea of this excerpt is that Chinese students studying in Japan, led by Sun Yat-sen, are advocating for the overthrow of the Qing Dynasty, which they view as an alien race that has occupied China. They believe that their cause is just and in line with the history of Chinese resistance against foreign invaders.