The present invention provides a composition comprising a mixture of HFC and HFO and having improved lubrication performance. Specifically, the present invention provides a composition comprising HFC and HFO, wherein the composition comprises 1) at least one of HFC-134a and HFC-134 as the HFC, 2) at least one of HFO-1234yf and HFO-1234ze as the HFO, and 3) at least one member selected from the group consisting of HCFC-1122, HCFC-124, CFC-1113, and 3,3,3-trifluoropropyne as a third component.