例：My aunt has worked in a clinic since 1949.
(2) so far /yet /already等 +现在完成时
例： So far, she hasn’t enjoyed the summer vacation.
(3) This/it is the first (third…) time sb. have done sth.（现在完成时）
例：This is the first time I have been here.
This/it was the first (third…) time sb. had done sth.（过去完成时）
例： It was the second time someone had interrupted me that evening.
(4) by the time /by the end of（到……为止）
例：The experiment had been finished by 4 o’clock yesterday afternoon.
(5) in the past time( two days/years…) +现在完成时
例：In the past 10 years, there have been great changes in our family life.
(6) hardly … when…. / no sooner … than句型用过去完成时,意为一….就…,且倒装。
例：Hardly had I reached the school when the bell rang.teacheray.com
No sooner had we sat down at the table than the phone rang.
(7) 未实现的愿望打算等用过去完成时,如expect, hope, mean, intend, plan, suppose, wish, want, desire等
例：I had thought I could pass the final examination but I failed.