谷子是起源于我国的古老作物,脱壳后为小米。但长期以来,科研人员对谷子遗传资源的群体结构缺乏了解,限制了对谷子基因资源的高效发掘和深度利用。近期,我国科学家率先绘出谷子基因组重要图谱,这对未来禾谷类作物的品种改良、能源作物的遗传解析产生深远的影响。材料揭示了( ) ①世界上只有尚未认识之物,没有不可认识之物 ②真理都有自己适用的条件和范围 ③认识是主体对客体的直接现实性改造 ④认识水平制约实践活动的效果
He had decided to give it up, but on ______ second thought, he decided to try ____ 3rd time.
What does it ________ if I spend $ 100 on it ---it’s my money.
More and more people choose to shop in a supermarket as it offers a great _____ of goods.
Mr. Wang has been selected_________ chairman of the conference.
Paper-making began in China and from here it ________ to North Africa and Europe.