15/8/19 I KNOW vs I KNOW IT
Note the difference between these two short answers. I know refers to facts – it could be complemented by a that-clause. “You’re late.” “I know.” (= I know that I’m late.) (NOT …I know it.) I know it generally refers to things – it replaces a noun. “I went to a nice restaurant called The Empire last night.” “I know it.” (= I know the restaurant.) (If you said I know, it would mean I know that you went to that restaurant.)