— Is this ____________book?
— No, it's ___________book.
A:your, your
B:your, my
C:my, your
古诗云:“才从塞北踏冰雪,又向江南看杏花。”据此完成下列各题。
The old man keeps walking around this street. I think he is new here and now he has trouble ____ (find) his way.
酵母菌A的筛选→酵母菌A的培养→菌体裂解→离心沉淀→萃取→过滤→浓缩→胡萝卜素的鉴定