— is it from Suqian to Jiuzhai Valley?
—About l,900 kilometers away. But I'm not sure.
A:How often
B:How soon
C:How long
D:How far
读“我国南部沿海区域”图,完成以下问题.
下列说法正确的是( )
是否存在两个质数,它们的和等于11….1(20个1)?