问题补充：
Where was it you our maths teacher?
A. where; came to
B. that; come across,
C. that; came across
D. where; come to
答案：
A. where; came to
B. that; come across,
(答案→)C. that; came across
D. where; come to
解析：考察强调句型和动词短语。第一空的that与it was构成强调句型。Come across遇见。结合句意可知C正确。句意：你究竟是在哪里遇见我们的数学老师的？
