A. I was weak enough B. I was too weak

C. So weak was I D. Such weak was I

【答案】C

【解析】

考查倒装句。句意：我如此的虚弱，以至于那一刻我无法支撑自己。so/such…..that如此……以至于……，引导结果状语从句，so后紧跟形容词，such后跟名词，因此此处用so；so….that引导状语从句时，so位于句首时，句子要到装。故选C。