I don't want to read this book. There is _______ in it.
A:something interesting
B:nothing interesting
C:interesting something
D:interesting nothing
如图,已知菱形ABCD,AB=5,对角线BD=8,作AE⊥BC于点E,CF⊥AD于点F,连接EF,求EF的长.
下列函数,①y=2x,②y=x,③y=x﹣1,④y=1x+1是反比例函数的个数有( )