| Subject | English | Russian |
| gen. | cannot know | не должен знать (he, she etc. cannot know • Peter cannot know that you know; Richard cannot know I'm here Taras) |
| proverb | one cannot know the inside of a man's mind | чужая душа – потёмки |
| gen. | one cannot know the inside of a man's mind | чужая душа – потёмки |