So you can say: " Call someone" or you can " call someone up" , basically means the same thing.

所以你可以说：“Call someone”或者你可以“call someone up”，基本上意思是一样的。

" Cold calling" is to call someone up on the telephone who isn't expecting your call, usually someone you have never talked to before.

“Cold calling” 是指打电话给不希望你来电的人，通常是你以前从未与之交谈过的人。