I look forward to PK I'm looking forward to:
两个应该都OK,有说 I'm looking forward to 比较“友善”,I look forward to 比较正式,如在正式信件中常用:I look forward to hearing from you. 平时会话中可说(Cambridge 例句):
I'm really looking forward to my holiday.
She was looking forward to seeing the grandchildren again.