A.不應(yīng)少于總數(shù)的30%,且不應(yīng)少于10根 B.不應(yīng)少于總數(shù)的20%,且不應(yīng)少于10根 C.不應(yīng)少于總數(shù)的30%,且不應(yīng)少于20根 D.不應(yīng)少于總數(shù)的20%,且不應(yīng)少于20根
A.100% B.30% C.不應(yīng)少于總數(shù)的30%,且不應(yīng)少于20根 D.不應(yīng)少于總數(shù)的30%,且不應(yīng)少于10根
A.45°;1/2 B.90°;1/3 C.45°;1/3 D.90°;1/2