Oil shale in China is basically a type of rock that contains a substance called kerogen. This kerogen can be turned into a type of oil through a process called "retorting."
Now, think of the oil shale as a chocolate chip cookie dough and the kerogen as the chocolate chips. When you bake the cookie dough in the oven, the heat causes the chocolate chips to melt and mix with the dough, creating a delicious chocolate chip cookie!
In the same way, when the oil shale is heated up, the kerogen melts and turns into oil. This oil can then be extracted and used for things like gasoline or diesel fuel.
China has a lot of oil shale, and they've been working on developing ways to efficiently and economically turn it into oil. It's an important resource for China because they have a lot of people and a growing economy, so they need a lot of energy to power everything.
However, it's also important to remember that using oil shale can have negative environmental impacts, so it's important for China to balance their energy needs with protecting the environment.