单选题 ______ that my head had cleared, my brain was also beginning to work much better.
A. For B. Now C. Since D. Despite

【正确答案】 B

【答案解析】[解析] for引导的从句表示推测性原因，不能放在句首。since意为“因为，由于”，不与that连用。despite意为“尽管”，是介词，只能引导让步状语从句。