题目

It was only __________he reached school ___________he realized that it was Sunday. A . when; did B . when; that C . that; when D . that; which 答案：B下列能够说明细胞核是遗传控制中心的一组是（ ）①克隆羊多利的培育过程  ②“试管婴儿”的培育过程  ③伞藻嫁接实验  ④植物组织培养技术．A．①③B．②④C．③④D．①②