In Negations^x, Auxiliaries^x

"Need" in its negation means 'not having the necessity to' and acts here as a modal auxiliary. Modal auxiliaries are always followed by an infinitive without to and do never take an -s for 3rd person: he will go to school / he won't go to school he can go to school / he can't go to school he may...

Miriam, The book is by Rodney Huddleston and Geoffrey Pullum. The capital letters in square brackets refer to a list of criteria on the preceding page concerning auxiliary verbs vs. modal auxiliaries. Here's the list: AUXILIARY PROPERTIES Primary verb negation. Subject-auxiliary inversion ...

"He had not been ill, he might have ccome." I think this sentence should read "IF he had not been ill, he might have come." In your sentence, the conjunction that introduces the conditional clause is missing. The second sentence is fine. When a conditional clause contains one of the auxiliary...