A:盐酸
B:FeCl3溶液
C:溴水
D:四氯化碳
There are many ____ (different) between living in a big city and living in the countryside.
下列说法中,错误的是( )
设数列an和bn分别为等差数列与等比数列,且a1=b1=4,a4=b4=1,则以下结论正确的是( )