The chords are numbered with Roman Numerals: I, IV and V ( that's 1, 4 and 5) these chords are also called the Tonic, Subdominant and the Dominant.
The chords are numbered with Roman Numerals: I, IV and V ( that's 1, 4 and 5) these chords are also called the Tonic, Subdominant and the Dominant.
和弦用罗马数字表示就是：I,IV和V（1，4和5）。这三个和弦也叫做主和弦，下属和弦和属和弦。