【正文】
thought that they (try)their best. 答案 :had tried (not realise)she wasn’t Chinese until she spoke. 答案 :had not realised thanked me for what I (do) for her son. 答案 :had done (learn)300 words by the end of last month. 答案 :had learned changes (take) place since 1996. 答案 :have taken told me he (live) in Beijing since he was born. 答案 :had lived was the first time I (visit) the Great Wall. 答案 :