A.10s B.30s C.60s D.2分鐘 E.5分鐘
A.牙尖斜度的2/5 B.牙尖斜度的1/3 C.牙尖斜度的3/4 D.牙尖斜度的1/5 E.牙尖斜度的2/3
A.0 B.25% C.50% D.75% E.100%