A:当染色体:核DNA=1:2时,姐妹染色单体的数量是染色体的2倍
B:当染色体:核DNA=1:2时,细胞中一定有同源染色体
C:当姐妹染色单体分离时细胞一定有4个染色体组数
D:染色体和核DNA的比值还可以是1:1或2:1
Carol doesn't know what she should take for her trip. (改为同义句)
Carol doesn't know____ ____ ____for her trip.