What changes have taken place in China society before and after the Opium War? (Hint: economic structure, social nature, class contradiction, revolution.

On the economic structure, the self-sufficient natural economy gradually disintegrated and was forced to be involved in the world capitalist market;

In terms of social nature, an independent sovereign state has become a semi-colonial and semi-feudal society, and national sovereignty has been destroyed;

Class contradiction has changed from the contradiction between landlord and peasant class to the contradiction between Chinese nation and imperialism;

The revolutionary task was transformed into anti-imperialism and anti-feudalism.