使用SharpNLP识别英语句子中的时态

Question

In my assignment, here I use SharpNLP to define part of speech, like noun, adjective, verb and so on. Then, i wanna classify sentence based on kind of tenses, firstly in this case, PAST TENSE as example.

Let see my code..

        listSentence = ParseInput(allInput);

        foreach (string word in listSentence[0].Split(separator))
            if (word.Trim() != "")
                listWord.Add(word);  

        string[] lWord = listWord.ToArray();
        string[] lPOS = this.NLP.PosTagTokens(lWord);

allInput = "I was busy yesterday."

Takes it simple, in contains "I was busy yesterday".
Then split into "I", "was", "busy", "yesterday" in
Then I used SharpNLP, that's running well so that contains {"NN", "VBD", "JJ", "NN"}
That should be recognized as TRUE
Based on that output, I'm confused how to recognize as PAST TENSE - TRUE or FALSE.

Explanation :

NN : Noun, singular or mass
VBD : Verb, past tense
VBP : Verb, non-3rd person singular present
VBZ : Verb, 3rd person singular present
VBG : Verb, gerund or present participle
VBN : Verb, past participle
JJ : Adjective
PRP : Personal Pronoun

If allInput = "I am busy yesterday"
string[] lPOS = {"PRP", "VBP", "JJ", "NN"}
That should be recognized as FALSE

If allInput = "They am busy yesterday"
string[] lPOS = {"PRP", "VBP", "JJ", "NN"}
That should be recognized as FALSE

If allInput = "I was busy tomorrow"
string[] lPOS = {"PRP", "VBD", "JJ", "NN"}
That should be recognized as FALSE

Sir, please help me. Give me idea, and rules to recognize past tense based on all output above. Let me learn by your example. Thanks a lot all. :) :)

Answer 1

There is a basic contradiction in the goal. The parser operates at the syntactic(structure) level. But you want to classify based on semantics(meaning) as well.
I was busy tomorrow is past tense according to the parser, because syntactically, there is a verb in past tense. But, the semantics of the last word, makes it a semantically wrong sentence.

In my opinion, for your goal, I am busy yesterday is Present tense and I was busy tomorrow is past tense.