單項選擇題
A.5mm B.10mm C.20mm D.30mm
A.1/2 B.3/5 C.3/4 D.2/3
A.1mm B.1.5mm C.2mm D.2.5mm
A.2mm B.3mm C.4mm D.5mm
A.8±1.5 B.6±1.5 C.4±1.5 D.2±1.5
A.4±0.5 B.3±0.5 C.2±0.5 D.2.5±0.5