A:(x+1)2+y2=1
B:x2+y2=1
C:x2+(y+1)2=1
D:x2+(y-1)2=1
The movie covers all of Chinese history. It is _______ worth seeing again.
①量变总会引起质变,要防止小官巨贪
②质变是量变的必然结果,要防止积小贪成巨贪
③量变达到一定程度一定引起质变,要加强监管
④量变到质变的过程就是发展,要防微杜渐