设等比数列{}的前n 项和为 ,若=3 ,则 = ▲ .
图1是两种高等生物细胞亚显微结构模式图。图2—4是图1中部分结构的放大,据图回答。([ ]内填图中标号, 上填适当内容的文字。)
已知向量,且,则m= ( ) A. B. C. 6 D.8
还原善意的本来模样 (1)故事发生在加拿大魁北克省的一个小城。 (2)一个风雪飘飞的傍晚,寒冷和积雪让往日川流不息的马路变得静谧而安详。在
I’m a real book lover. Every time my friends visit me, my nose is buried in a book. Wherever I go, I always have a book with me. Novels, history books, stories about people, journals and news—I
据中国天气网2011年1月14日消息,我国北方九省市遭遇干旱。下列解决首都“干渴”的办法中不合理的是( ) A.控制北京人口数量,节约用水
夏季晴朗时候,对于温室大棚内一昼夜空气中二氧化碳浓度变化规律描述曲线正确的是
Ever since news of widespread food recalls caused by a carcinogenic dye broke, there has been confusion(混淆) over possible links to the country of the same name, but Sudan officials say there is no