Verbless sentence [duplicate]

Solution 1:

The usual definition of the word 'sentence' demands that there be a verb*, so the question becomes nonsensical.

However, rephrasing to 'Don't use structures other than sentences,' we must say that this is a very shaky rule-of-thumb rather than a grammatical requirement. In conversation, sentence fragments / sentence substitutes such as Tomorrow, Yes, If you must, On the table are often given as answers and are quite acceptable. Follow-on fragments are also quite acceptable in informal writing: She is 70 years old. Perhaps older.

Look up articles on 'sentence fragments' and 'crots' on the internet for guidance on actually using these structures.

*The fact that 'sentence fragments' are sometimes called 'minor sentences' is, I feel, confusing.