It's been nice talking to you.为什么用is不用has?

it's a nice car._____ have been in it It's been nice talking to you的意思 It’ s a nice It's very nice! It's nice to It's been nice meeting you.这句话中的meeting是动名词变名词词性吗? It's been nice to know you.I have to go,see you next time. It's been nice talking to you.为什么用is不用has? It's very nice.It's yellow. It's nice out?还是说It's nice weather? ( )oh,it's very nice It's very nice ( )you. it's really nice out. It's been awhile. it's been coverd.. It's nice and warm.中Nice and It's nice and warm.中Nice and It’s nice to meet you中的nice是什么意思