题干
I am good at playing basketball，and my brother is good at it．
A：too
B：still
C：also
D：even
答案(点此获取答案解析）
C
I am good at playing basketball，and my brother is good at it．
A：too
B：still
C：also
D：even
成立的所有常数M中，我们把M的最小值1叫做
的上确界，若
，则
的上确界为（ ）
