in the last few days为什么用last?

in the last few days为什么用last? in the last few my time__a lot in the last few days in the last few years he was on leave ...days.A.the few last B.the last few C.few in the last few years 为什么要加 the I am going to US today.I was in Japan the last few days.I wi I am going to go shopping in the last few days I have h_____ seen my best friend in the last few days.I don in the last few years 为什么是用现在完成时而不用过去完成时? ..the last few days 现在完成时的时态吗? I have been very busy the last few days