文法問題there附原文

Subjects in many old photos were not smiling at the camera for two reasons. Ann Thomas, curator of photographs at the National Gallery of Canada, says, “ In the early days of photography, __15__existed a tradition of formality- handed down from portrait painting- in which posing for a photograph was... 顯示更多 Subjects in many old photos were not smiling at the camera for two reasons.
Ann Thomas, curator of photographs at the National Gallery of Canada, says, “ In the early days of photography, __15__existed a tradition of formality- handed down from portrait painting- in which posing for a photograph was considered a solemn occasion.”

The second reason, according to Thomas, is that prior to the 1880s, photographs required long exposures. So contributing to the process, this could involve 20 minutes or more. This necessitated the subject remaining still, and since maintaining a smile for such an extended period was difficult, it was discouraged. The arrival of smiling face in photos came after the invention of the snapshot in the 1880s with the introduction of the Kodak dry-plate camera.

15 --- A) it B) that C) when D) there

答案是 D
為什麼呢??
為什麼不用it和days的s有關嗎??不懂

自己解析如下
Ann Thomas 主詞
, curator of photographs at the National Gallery of Canada,同位語補充說明主詞身份
says,動詞
“ In the early days of photography, 副詞子句.

__15__ 主詞existed a tradition of formality
- handed down from portrait painting- in which posing for a photograph was considered a solemn occasion.”
2 個解答 2