题干
At first I didn't find Jack. Later, I found him in the library.
A：Soon
B：After some time
C：Suddenly
D：Quickly
答案(点此获取答案解析）
B
At first I didn't find Jack. Later, I found him in the library.
A：Soon
B：After some time
C：Suddenly
D：Quickly
的公比为正数，且
，
=1，则
=" "