such and such —(also: so and so) is used to refer to a person or thing whose name one does not remember or does not want to be precise:
- We don’t have to wonder, like the early explorers did, at what time we will reach such and such a location.
thus and thus—(also: thus and so) act in a particular way or according to directions that have been given:
- The truth of the matter is that it is almost impossible to say “do thus and thus and you will have a best-seller.”