Translation:This blue pair of pants looks good.
Was it? I only remember it used for, for example, a pair of shoes. So far as I am aware, Chinese doesn't follow the slightly odd convention of referring to single garments as 'pairs'. And surely it's fine in English (possibly depending on dialect?) to say 'these trousers/pants instead of 'this pair of...'
No, but "These blue trousers are good looking." = Accepted.: 12 feb. 2020. In this way I also avoid "pair of pants": I hate the translation "pair" if there is only 1 item. [And moreover: "pants" = American English. No, I am not a native English speaker - which can also be seen in the way I indicate the date - but I prefer British instead of American English].