It wasn’t until he came back he knew the police were looking for him.
A. when
B. that
C. since
D. before
网友回答
A. when
(答案→)B. that
C. since
D. before
解析：考查强调句型。强调句型：It is/was 被强调成分 that/who 其它成分；强调句型最大的特点是把it is/was that/who去掉，句子仍然成立。本题强调的是时间状语not until he came back.句意“直到他回来，他才知道警察在找他。故B正确。