现在完成进行时:
	   have /has + been + v-ing(现在分词) 
	(1)  I have been working   Have I been working?
	I have not been working  Have I not been working?
	He (she, it ) has been working 
	 Has he (she, it) been working ?
	He (she, it) has not been working  
	Has he (she, it) not been working?
	We have been working  Have we been working?
	We have not been working   
	Have we not been working ?
	 (4)  You have been working   Have you been working?
	You have not been working 
	Have you not been working?
	 (4)  They have been working   Have they been working?
	They have not been working 
	Have they not been working?
	 e.g.   I’ve been writing letters all this morning.
	You’ve been saying that for five years.
	Too much has been happening today.