66. 有關圓木鋸切製材品,下列敘述哪些正確? (A)製成灘稜方木製材率約 70~75% (B)製成正方木製材率約 70~75% (C)製成灘稜方木製材率約 60~65% (D)製成正方木製材率約 60~65%