I could do it. = Mohl bych to udělat.
I could go there. = Mohl bych tam jít.
I could give money. = Mohl bych dát peníze.
I could meet him. = Mohl bych se s ním setkat.

Could you go there, please? = Mohl bys tam jít, prosím?
Could you do it, please? = Mohl bys to udělat, prosím?
Could you help me, please? = Mohl bys mi pomoci, prosím?