反应①、②分别是从海藻灰和某种矿石中提取碘的主要反应，下列说法正确的是 ① 2NaI＋MnO2 ＋3H2SO 4 =2NaHSO4 ＋MnSO4 ＋2H2O ＋ I2 ② 2NaIO3 ＋ 5NaHSO3
、一商场对某款羊毛衫进行换季打折销售，若这款羊毛衫每件按原销售价的8折（即按照原销售价的80％）销售，售价为120元，则这款羊毛衫的原销售价
已知f(x)＝xln x，若f′(x0)＝2，则x0＝( )． A．e2 B．e C. D．ln 2
—__________will you stay in New York? —For a week. A. How often B. How much C. How far D. How long
John is a paper boy. He delivers newspapers to different houses in his street every day. He has about 80 customers. Half of his customers only take the newspapers on weekdays, and about half take th
俗语说：吃鱼吃肉不如吃豆。豆腐中含有丰富的营养。 (1)食用豆腐能获得人体所需的多种氨基酸，其中含量最多的是亮氨酸(化学式为C6H13O2N)。亮氨酸
People waste __________ electricity every day. It’s time to take action. A) a large number of B) huge amounts of C) many D) quite a lot
的相反数是（ ）
