题干
It was only when I read this story for a second time________to appreciate its beauty.
A：did I begi
B：that I bega
C：then I bega
D：had I begu
答案(点此获取答案解析）
B
A：did I begi
B：that I bega
C：then I bega
D：had I begu
=Acos(
)的图象如图所示，
，则
=
