基因工程育种区别于诱变育种的特点是 A.能够产生新基因 B.能定向地改造生物 C．操作简便易行 D.不需要对处理
One day a woodcutter took his grandson into the forest for his first experience of selecting and cutting oak trees. They would later 12 them to the boat builders. As they walked along, th
2009年11月，国际TOP组织最新发布显示，我国第一台千万亿次超级计算机系统“ ”排名第五、亚洲第一，它的诞生是我国战略高新技术和大型基础
唐雎不辱使命 秦王谓唐雎曰：“寡人以五百里之地易安陵，安陵君不听寡人，何也?且秦灭韩亡魏。而君以五十里之地存者，以君为长者，故不错意也。
观察下列算式：，，，，，，，……用你所发现的规律写出的末位数字 。
I had expected to come over to see you last night, but someone ______ and I couldn’t get away. A. called B. had called C. would call D. would have called
阅读下文，完成文后各题。 在儒家的传统中，孔孟总是形影相随，但仔细比较却也发现很多不同的地方。最明显的，《论语》中所叙述的孔子，有一种
Students in our school ________ know shouting is not allowed in the library. A. can B. may C. must D. need
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