作者：Raymond Murphy
出版社：Cambridge University Press
副标题：A Self-Study Reference and Practice Book for Intermediate Students of English with Answers
发行时间：April 15th 2004
来源：下载的 pdf 版本
Goodreads：4.33 (1392 Ratings)
豆瓣：9.7（20人评价）
The present perfect continuous is used to refer to an unspecified time between 'before now' and 'now'. The speaker is thinking about something that started but perhaps did not finish in that period of time. He/she is interested in the process as well as the result, and this process may still be going on, or may have just finished.
