nice seeing you

nice seeing you 的语法 1.it's nice seeing you.__ nice seeing It is nice seeing you again 与It is nice to see you again这两句是 It is nice that you have someone ____ you off. A.seeing B.sa It is nice that you have someone ___you off.A:seeing B:saw C It will be nice seeing them again It is nice seeing you again这句话对么?（网上都说是对的） 但为什么it is great.. I'll be seeing you Looking forward to seeing you, Are you seeing anyone now? will you be seeing it