A.0.2~0.4 B.0.5~0.7 C.0.6~0.8 D.0.6~0.9
A.1/4~1/2 B.1/3~1/2 C.1/2~2/3 D.1/2~1
A.四點(diǎn)法 B.五點(diǎn)法 C.六點(diǎn)法 D.九點(diǎn)法