A:So I did
B:I did so
C:So do I
D:So did I
物理学中引入“质点”概念,从科学方法来说,是属于( )
Broadway has been well-known for its theatres since the early ____ century. (twenty)
先化简,再求值:(x+1)2+x(2﹣x),其中x= 2 .