When writing intervals on the staff, it is common to confuse intervals with the same number of half steps.
（書寫音程的時候，有時會將其半音的數目搞混）
For example, one may accidentally write C to F-sharp (an augmented fourth) instead of C to G-flat (a diminished fifth).
（比如，有人會把C到升F（增四度）寫成C到降G（減五度））
Although both intervals sound the same and look identical on the keyboard, one is a fourth and the other is a fifth.
（儘管這兩個音程聽起來都一模一樣，但一個是四度，另一個是五度）
Fortunately, an easy three-step process exists to reduce the risk of this mistake.
（還好，這種錯誤可以用一種“三步”的方法來避免）
Let's write a minor third from C.
（我們從C開始，寫一個它的小三度）
First, write the generic interval on the staff. For this example, we will write a generic third.
（首先我們需要寫一個通用音程。本例中我們用三度）
Next, figure out the number of half steps on the keyboard. Since a major third is 4 half steps, our minor third will be 3 half steps.
（然後算出鍵盤上半音的數量。因為大三度是四個半音，那麼小三度就是三個半音）
Finally, compare the staff and keyboard results. Add any needed accidentals to the staff.
（最後比對一下五線譜上和鋼琴鍵盤上的結果，在需要的地方添加變音記號即可）
C—E-flat is a minor third.
（C-降E是一個小三度） | 
For our next example, let's try a major sixth from F-sharp.
（接下來我們試一下升F的大六度）
First, write the generic sixth on the staff.
（首先寫一個六度）
Next, figure out the half steps on the keyboard. A major sixth is 9 half steps.
（接下來算出鍵盤上的半音數。A的大六度有九個半音）
Finally, add any needed accidentals.
（最後加上需要的變音記號）
F-sharp—D-sharp is a major sixth.
（升F到升D是一個大六度） |
For our final example, we will write a diminished fifth from B.
（最後一個例子，我們來寫一個B的減五度）
First, write the generic fifth on the staff.
（首先寫一個五度）
Next, figure out the half steps on the keyboard. Since a perfect fifth is 7 half steps, our diminished fifth has 6.
（然後算出鋼琴鍵盤上的半音數。純五度有七個半音，所以減五度就有六個半音）
Finally, add any needed accidentals. In this example, no accidental is needed.
（最後加上需要的變音記號。在本例中不需要加變音記號）
B—F is a diminished fifth.
（B到F是一個減五度） |
Use this chart to reference the interval-writing process.
（下表是書寫音程的順序）