______ entering the concert hall, I noticed that refreshments were being served.
AOn正確答案
BAbout
CTo
DOf
答案與詳解
為什麼答案是 A
On entering 為固定用法，意為「一進入...時」，相當於 When/As soon as I entered，符合句意與文法。
載入中…
On entering 為固定用法，意為「一進入...時」，相當於 When/As soon as I entered，符合句意與文法。
