不定项选择BY-2悬浮细胞用细胞壁酶解液酶解后，经高浓度蔗糖溶液离心后，状态良好的原生质体培养基留在中间层
单项选择题In general, the Song people were much more extravagant in the way they dressed, while the Tang people preferred the reserved and contained elegance. ( )A.对B.错
