octave sign造句

For instance, a melody proceeding upward from the first octave can, if moving by step, proceed to the second, third, and fourth octaves without requiring additional octave signs.
The rule for 4ths and 5ths is different, however : in the absence of an octave sign specifying otherwise, a melodic leap of a 4th or a 5th will always stay within the same octave as the previous note.
It's difficult to find octave sign in a sentence. 用octave sign造句挺难的