下列有关苯的说法中不正确的是( )
A:通常状况下,是无色、有特殊气味的液体
B:通常状况下,不能使溴水或酸性KMnO4溶液褪色
C:通常状况下,与浓硝酸混合则剧烈反应生成硝基苯
D:碳原子间的键是一种介于C﹣C和C=C之间的特殊的键
要求:内容要具体,描写要细致,字数不少于五百字。
单词归类。
student coat tie bus stop vet policeman panda pajamas shoes socks lion leopard post office jeans jacket sweater dancer zebra toilet rabbit pilot juggler snake swimming pool tiger movie theatre goat trousers sheep bank fox fire station squirrel monkey frog zoo horse giraffe shorts shirt library park hospital restaurant skirt dress pants train station teacher police station school nurse supermarket doctor
—They're ________.
已知椭圆 C:x2a2+y2b2=1(a>b>0) 的右焦点为F,过椭圆C中心的弦PQ长为2,且∠PFQ=90°,△PQF的面积为1.
(Ⅰ)求椭圆C的方程;
(Ⅱ)设A1、A2分别为椭圆C的左、右顶点,S为直线 x=22 上一动点,直线A1S交椭圆C于点M,直线A2S交椭圆于点N,设S1、S2分别为△A1SA2、△MSN的面积,求 S1S2 的最大值.