问题
选择题
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
答案：D
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.