A:x+y=2
B:y-1=-1x2(x-1)
C:y-1=1x2(x-1)
D:x+y+z=2
过圆内的一点(非圆心)有 ____条直径.
Do you think the bag is one of those____(climb)?
把2∶0.9化成最简单的整数比是____∶____.