现在完成时，现在完成进行时
现在完成时：
1、过去发生已结束，对现在产生因果影响
（一般过去对现在无影响）
2、到现在为止（谈论至今经历）
so far,up to/till now,by now,as yet=yet,
to date,before (now), ever,never,twice
over/in the past three days
必考句型：It is the first time that sb. have done
现在完成进行时 have been doing
1、始于过去，现在刚刚结束
现完进：强调动作进行“着”
现完：“了”，强调对现在影响
2、始于过去，现在也进行中
for,since，how long
工作，生活，学习：现完=现完进
live,stay,work,study,teach+for/since
I have been working here for 5 years
=I have worked here for 5 years
did,have done,have been doing辨析
