It was ______ he was asserting the impossibility of miracles that he discovered his extraordinary powers.
A、while
B、which
C、in which
D、that
【正确答案】：A
【题目解析】：本题考查强调句型。It is/was+被强调部分+that/who+其他部分构成英语强调句型。题干中，剔除It was...that之后句子完整，便可判断该句是强调句型。同时由题意可知被强调部分是一个时间状语，故选A。答案为A。
