| Subject | English | Russian |
| gen. | tell which is which | отличить одно от другого (He attacked everything in life with a mixture of extraordinary genius and naive incompetence and it was often difficult to tell which was which. 4uzhoj) |
| gen. | they are so alike I can never tell which is which | они так похожи, что я их не могу различить |
| gen. | which is which? | который из двух? |
| gen. | which is which? | кто из них кто? |
| gen. | which is which? | который из них кто? |