单选题 It was not until the accident happened ______
A. when I became aware of my foolishness
B. when my foolishness became obvious
C. that did I realize my foolishness
D. that I became aware of my foolishness

【正确答案】 D

【答案解析】本题考查的是强调句型“It is/was…that/who…”，当强调的是人的时候用who，其他都用that，本句强调的是时间状语从句，因此用that。只有当not until从句提前到句首时，主句才部分倒装。因此选D。