-- you called yesterday evening?
---My sister. Why?
A. Who it is that
B. Who is it that
C. Who was it that
D. Who it was that
网友回答
A. Who it is that
B. Who is it that
(答案→)C. Who was it that
D. Who it was that
解析：考查强调句型。It is/was 被强调成分that/who其它成分；这是强调句型的基本结构。强调句型最大的特点就是把it is/was…that/who去掉，句子仍然成立。本题考查它的特殊疑问句。句意：—昨天晚上你到底叫了谁？—我的妹妹，怎么了？