No, past could refer to anything that has already happened and could be a single event or multiple events. Last usually refers to something that just happened usually referring to a single event or item
25 มกราคม 2015
0
1
0
Very occasionally they can. There is no difference in meaning between:
'I've been working hard these last few weeks'
and
'I've been working hard these past few weeks'.
However, in most other cases, you cannot replace 'last' with 'past'.