The structure that interests us is: “little did Mrs Anthony knew…” Two separate but grammatically interconnected aspects of the structure are noteworthy. These are: did and knew. This is a faulty structure because the tense marker that has changed do to did has also changed know to knew. However, grammatical logic requires that only one of them should be changed to the past, and that is do. Once that is done, the verb know does not require inflection. This is true, not just of sentences requiring changes for the past, but also of those requiring inflection for the third person singular in the present.
The following sentences are also faulty: *1) Little did he realized that danger was ahead. *2) He did not understood the explanation. *3) She does not speaks French. *4) Little does he realizes that she is telling a lie.*5) She does speaks French fluently. *6) The country does has rich agricultural resources. *7) I did understood your explanation. *8) The criminal did altered the document.
The correct forms of these sentences are: 1) Little did he realize that danger was ahead. 2) He did not understand the explanation. 3) She does not speak French. 4) Little does he realize that she is telling a lie. 5) She does speak French fluently. 6) The country does have rich agricultural resources. 7) I did understand your explanation. 8) The criminal did alter the document.
The general rule is this: Whenever the supporting do is brought into a sentence for the purpose of negation or question formation or for the purpose of emphasis (e.g. “The criminal did alter the document” is an emphatic form of: “The criminal altered the document.”), it is that verb (do) that carries the tense and concord/number markers. In consequence, the main verb or verbs do not experience change in form. Examples are: 1a) He knew the truth. 1b) He did not know the truth. 2a) She spoke her mind. 2b) She did not speak her mind. 3a) I accepted the offer. 3b) I did not accept the offer. 4a) He knows the truth. 4b) He does not know the truth. 5a) She speaks her mind. 5b) She does not speak her mind. 6a) She sings well. 6b) She does not sing well. 7a) He knows the truth. 7b) He does know the truth. 8a) It moves fast. 8) It does move fast.
Let’s have more examples: 1a) Militants attacked the army chief’s convoy. 1b) Militants did not attack the army chief’s convoy. 2a) The cold weather prevented us from enjoying the holiday in England. 2b) The cold weather did not prevent us from enjoying the holiday in England. 3a) The national assembly delayed the passage of the bill. 3b) The national assembly did not delay the passage of the bill. 4a) The police frustrated the investigation. 4b) The police did not frustrate the investigation. 5a) The lady loves flowers. 5b) The lady does not love flowers. 6a) Diligence opens all doors. 6b) Diligence does not open all doors. 7a) He attended the seminar. 7b) He did attend the seminar. 8a) He wrote a report. 8b) He did write a report.
Note that in (a) of numbers (1)-(4), each of the main verbs carries the tense: attacked, prevented, delayed, and frustrated. But in (b) of the corresponding numbers, the form do is introduced. The do form now becomes did because the tense is transferred to it. In consequence each of the main verbs, now relieved of the tense, is presented in its basic, uninflected form: attack, prevent, delay, and frustrate.
The pairs of sentences in numbers (5) and (6) are in their present simple (everyday) tense. The verb in each of sentences (5a) and (6a) carries s, an indication that it is inflected to reflect the third person singular subject: loves, opens. The do form is introduced in each of their (b) counterparts. The subject, being in the third person singular form, requires that the verb should carry the s or es or ies as the case may be. Characteristically, this feature is transferred to the form do so that it becomes does. This grammatical fact is also applicable to the emphatic forms in numbers (7) and (8).
The influence of the do-form is also applicable to structures of questions. The questions could be those requiring yes/no answers (known as yes/no questions) or wh-questions (those beginning with wh-words: what, when, where, which, how).
Read the following sentences: 1a) The journalist wrote an interesting report. 1b) Did the journalist write an interesting report? 1c) The journalist did not write an interesting report. 2a) The result of the election surprised the party leaders. 2b) Did the outcome of the election surprise the party leaders? 2c) The result of the election did not surprise the party leaders. 3a) The victim reported the case to the police. 3b) Did the victim report the case to the police? 3c) The victim did not report the case to the police. 4a) The school suspended sporting activities. 4b) Did the school suspend sporting activities? 4c) The school did not suspend sporting activities. 5a) The fraudster deceives his victims. 5b) Does the fraudster deceive his victims? 5c) The fraudster does not deceive his victims. 6a) The lady loves flowers. 6b) Does the love flowers? 6c) The lady does not love flowers.
The rule we have specified and illustrated so far is also in operation in those sentences. In all the (a) sentences in which the main verbs are the only verbal elements available, those verbs are inflected either for tense or number. In all the (b) and (c) sentences in which the do-form is introduced for the purpose of forming either questions or negation, it is the do form that becomes either did or does. The main verbs in the latter cases remain in their basic, uninflected forms.
Please note that the (b) sentences in (1)-(6) are yes/no questions. We can also have wh-questions: (1) What did you tell the chairman yesterday? 2) What did the Chief Press Secretary suggest to the Governor? 3) What did your father give you? 4) What did the teacher explain to the inquisitive student? 5) Why did you leave the campus so early? 6) Why did the soldiers attack the Odi community in Bayelsa State? 7) Why did Jesus curse the fig tree? 8) Why did President Muhammadu Buhari delay for so long before appointing his ministers? 9) When did you leave Lagos? 10) When did Nigeria gain her independence? 11) When did Nigeria join the United Nations? 12) When did the plane take off? 13) Where did you pass the night? 14) Where did Chief Obafemi Awolowo live when he was Premier of Western Region? 15) Where did you find your wallet? 16) Where did the meeting take place? 17) How did you arrive so early? 18) How did you run the company during the time of recession? 19) How did the information get to the management? 20) How did the Federal Government win the civil war?
All the sentences are in their past forms. How is this indicated? The indicator is the supporting verb-form do which is in its past form: did. The main verb following did is consistently in its infinitive, uninflected form. The rule remains the same in its application even when the sentence is in its present form.