It is ...since X 的句型真的很让人困惑,但问题不在于 since 的含义,
since X 的意思是“从 X 到现在”,这是没有争议的.
It is five years since he became a soldier =》他成为军人到现在已经 5 年了
句子的 He became a soldier 意味着他现在还是个军人.(became,成为,是延续性动词.)
It is five years since he was a soldier =》他不当兵已经五年了
这里,he WAS a soldier 的 was 意味他以前是军人(现在已不是).
was 不是延续性动词.
同样地
It was nine years since I had enjoyed a good drink.
是说
我没有享受 a good drink 已经9 年了.
(这个理解来自过去时态 was 和过去完成时态 had enjoyed .was 和 had enjoyed 没有延续性).
“tidy up smoking” 这个说法我好像没看到.
对母语非英语的人,这些区别很使人困惑,理解这些句子的不同含义需要语感(即长时间的语言接触),不能仅从单词的字面意思看出来.
It is 5 years since I have lived here.
没有错,意思是
我住这里已经 5 年了.(现在还住在这里.)