You'd better go to the post bar and ask … Da. Home is reading. Schools are made of paper. The root cause is not electricity. No one will ask you questions. Title. Hands. Type. Even if there is, I will give you troublesome steps such as finding test papers, taking photos and uploading them online. Basically no one can do it, so ... don't wait.

Also, you can search for a topic in Baidu library, or type dozens of words from the topic and search directly with Baidu. Maybe you can find it. Or you can go to official website, where the book was published, and official website may have the answer.