问题补充：
--What are you doing now?
-- I’m talking to Mary online. She from Canada a few days ago.
A. is coming back
B. come back
C. came back
D. went back
答案：
A. is coming back
B. come back
(答案→)C. came back
D. went back
解析：考查固定短语和时态。句子中有a few days ago，故用一般过去时，而come back固定短语返回。故选C。
