A:①②
B:①③
C:②④
D:③④
—Lingling, do you know ___________ woman in white? —Yes, she is __________ nurse in Children's Hospital.
判断.
把单位“1”分成8份,表示这样的3份的数是 38 .
下列关于实验操作步骤的叙述,正确的是