—So when did you meet Joan?—It was last Sunday she came to visit my sister.A. thatB. sin

问题补充：

—So when did you meet Joan?

—It was last Sunday she came to visit my sister.

A. that

B. since

C. when

D. Before

答案：

A. that

B. since

(答案→)C. when

D. Before

解析：考查从句辨析。为避免与第一句重复，答语句尾省略了that I met Joan，答语是一个强调句，强调的是时间状语last Sunday，强调句中包含了一个when引导的定语从句，故选C。