The third door is difficult. The theoretical basic courses of the music major are usually commonly known as the Primary Three Courses, which are music theory, sight-singing, and ear training. They are also required subjects for the music art examination. Music theory, also known as basic music theory, is the only purely theoretical course in Primary 3. It means sight-singing, requiring students to accurately and completely sing the pitch, rhythm, beat, etc. of the given melody in a short period of time. Ear training is different from sight-singing. It is usually a written test. To put it simply, it is listening and sketching, divided into five major sections: melodic intervals, harmonic intervals, chords, rhythm, and melody. The art college entrance examination refers to studying art majors and taking the general college entrance examination. The art college entrance examination is different from the ordinary college entrance examination, which requires not only learning cultural courses but also art professional courses. Therefore, the scores for cultural courses required for the art college entrance examination are lower than those for non-art college entrance examinations.