问题
According to the second paragraph，we can know that__________．
A:the Southern Hemisphere is tilted away from the sun in June
B:June 21 is the longest day of a year in the Southern Hemisphere
C:December 21 is the coldest day of a year in the Northern Hemisphere
D:there is only one day in a year when daytime lasts exactly as long as nightti me
B:June 21 is the longest day of a year in the Southern Hemisphere
C:December 21 is the coldest day of a year in the Northern Hemisphere
D:there is only one day in a year when daytime lasts exactly as long as nightti me
正确答案是：
