答案：C.
翻譯：世博會提供了如此多的樂趣,以至于大多數參觀者在全部看完之前就耗光了時間.
解釋：
1. 此題考查so...that...句型的倒裝.
該句型規(guī)定如下：把so所修飾的形容詞（及該形容詞修飾的名詞）或副詞提前至句首,并將主句部分倒裝（即類似于一般疑問句變化,把be/助動詞/情態(tài)動詞提前）,而that從句句序不變.
2. 即該題的正常句序為：
The World Expo offered so much of interest that most visitors simply ran out of time before seeing it all.
把so much of interest提前,并緊跟助動詞did,后面使用動詞原形offer,即變成：
So much of interest did the World Expro offer that most visitors simply ran out of time before seeing it all.
3. 不過,樓主句中可能漏打了單詞,so much of interest不通順,不過并不影響做題.