Answer:
The terms that China had to accept were basically giving up its ports, external involvement in their policies, and giving up trade with opium.
Step-by-step explanation:
The Second Opium War started in 1856 and ended in 1858. On one side was China, or rather the Qing Dynasty, while on the other were Great Britain, France, Russia, and the United States. Even though the countries that fought against China were mostly competitors and not on the best of terms with each other, they united so that they take down China and exploit it, and were successful in it.
The war ended with the Treaty of Tientsin. The Qing Dynasty was forced to accept terms in the treaty that were terrible for China. Some of them were that China effectively gives up control of its ports. The policies made in Beijing were influenced by foreign factors. The opium and its trade, China's most valuable resources at that time, fell in the hands of the afforementioned countries. The society was no longer isolated and protected from foreign cultural influences, but now Christian missionaries were allowed to propagate Christianity. All of this led to devastating consequences in the economy of China, but also in its society which in the coming decades became highly polarized which led to internal conflicts.