问题补充：
Oh! I you in Beijing.How long have you been here?
A. don’t know.. were
B. hadn’t known.. were
C. haven’t known.. are
D. didn’t know.. were
答案：
A. don’t know.. were
B. hadn’t known.. were
C. haven’t known.. are
(答案→)D. didn’t know.. were
解析：可联系答.案.网客服索取。
