题干
--- What was the Shanghai World Expo’s opening day like?
--- Wonderful. It’s years ______ I enjoyed myself so much.
--- Wonderful. It’s years ______ I enjoyed myself so much.
A：that
B：since
C：before
D：whe
答案(点此获取答案解析）
B
在定义域R内可导，若
，若
则
的大小关系是 （ ）