问题补充：
---What do you think made the girl so glad?
--- a beautiful necklace.
A. As she was sent
B. Being sent
C. Sent
D. To be sent
答案：
A. As she was sent
(答案→)B. Being sent
C. Sent
D. To be sent
解析：问句的意思为：你认为什么使这个女孩如此的高兴呢？根据句意应该是对主语进行回答，四个选项中只有B能做主语，填到空中意为被送给了一个漂亮的项链。故选B。
