当宇航员乘坐宇宙飞船飞向太空时，必须从生物圈中携带维持生命所必需的物质。这些物质应该有（ ）A．营养物质、淡水、适宜的温度B．阳光、适
—Sir,could you please put out your cigarette?This is a smoke-free(无烟的)school. —________. A.I’m sorry about this
One summer evening as I was cooking dinner, there was a knock at the door. I opened it and saw an old man. But his voice was pleasant as he said, “Good evening. I come to see if you have a room fo
Every morning, she ___________ her daughter before having breakfast. A. dresses B. wears C. puts on D. dresses up as
丘吉尔在1946年3月5日的演说中指出：“在全部历史中，没有一次战争比前不久使地球上这么多地区沦为废墟的这次大战更容易被及时地加以制止，它本
欣赏下面这幅漫画，介绍漫画内容，写出这幅漫画含义。 漫画内容：
下丘脑在人体生理调节过程中发挥着重要的作用。如图甲、乙、丙、丁代表人体内的某种结构或细胞，A、B、C、D代表调节物质。请据图回答： （1）图
有相同质量的两份NaHCO3粉末，第一份加入足量盐酸，笫二份先加热使其完全分解再加足量同浓度的盐酸，则两者所消耗的盐酸中氯化氢的质量比为（
的前n项和为
，则通项公式
_________ 
