问题补充:
Hello! I you in London. How long have you been here?
A. don’t know, were
B. hadn’t known ,are
C. haven’t known ,are
D. didn’t know, were
答案:
A. don’t know, were
B. hadn’t known ,are
C. haven’t known ,are
(答案→)D. didn’t know, were
解析:考查时态.根据下文你在这儿多久了?可知前文意思是我不知道你在伦敦.说的是在这以前我不知道你在伦敦,主从句都是强调的过去,故选D.