As a nonprofit, we depend on donations to make these videos and to run khanacademy.org. If we've helped you, can you help keep Khan Academy free ... ... <看更多>

Reading (video) | Khan Academy. In this video, we'll discuss the main idea of a text: the key information the author wants you to understand. ... <看更多>

When you're reading, it can be frustrating to encounter words you don't know! Try out these strategies, and use the word's context to figure out the word's ... ... <看更多>