配方法:x2-4x+3=(x-2)2+______.
∵x2-4x+3=x2-4x+4-4+3,
∴x2-4x+3=(x-2)2-1.
我国最大的综合性工业基地是( )
A.以宜昌、重庆为中心的工业基地
B.以武汉为中心的工业带
C.以攀枝花、六盘水为中心的工业基地
D.由沪宁杭等城市形成的工业带
Playing on a frozen sports field sounds like a lot of fun. Isn't it rather risky, _____? [ ]
A. though
B. also
C. either
D. too