说明：  ⑴ 理解和掌握线性码编码和解码的理论和方法。 ⑵ 对26个字母进行线性码的编码，再给出译码方法。
(⑴ understanding and mastering the linear code encoding and decoding of the theory and methods. ⑵ 26 letters of linear code encoding and then decoding method is given.)