已知集合A={(x,y)|x,y为实数且x2+y2=1},B={(x,y)|x,y为实数且x+y=1},则A∩B的元素个数为[ ]
A、4
B、3
C、2
D、1
答案:C
A continual worsening of the list or trim indicates().
A.negative GM
B.progressive flooding
C.structural failure
D.an immediate need to ballast
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