The test was ______difficult that she had problems finishing it on time.
【正确答案】 C
【答案解析】解析：句意：这个测试太难了以至于她很难按时完成。本题考查的是固定搭配。so+adj／adv．+that“太…以至于…”，引导结果状语从句。故C正确。