Rules of Right Form of Verb

Verbs are the most variable components of a sentence. They take different forms according to tense, person, voice, moods, modals, subject-verb agreement, etc. To grasp the concept of the right form of verbs, we need to master the rules first.The right form of verb encompasses most of the grammatical rules of English language. Every element of a sentence eventually relates to the verb. The verbs appear differently in a sentence on the basis of their subjects (subject-verb agreement), tenses, moods, voices, different structures, modals, etc.
Rule-1
If the sentence is present indefinite tense and subject is 3rd person singular number, s/es will have to be added to the verb. On the other hand, if the sentence is present indefinite tense but subject is without 3rd person singuler number, there will not be s/es added to the verb.
Example:
He (go) goes to school everyday.
They (go) go to school everyday.
Rule-2
If there is mentioned time like yesterday,last night, last week, last month, last year, last+ time, ago, once, once upon a time, long long ago etc. in the sentence, the verb will be past form (V2).
Example
Sriza (come) came here yesterday.
Mina (be) was born in 2003.
Rule-3
If there is verb at the begining of the sentence, there will be added To before the verb or ing next to the verb.
Example
(Walk) To walk / Walking is good for health.
Rule-4
If there is Since / for + time , the sentence will be present perfect continuous tense .
Example
I (work) have been working here for 3 hours.
He (try) has been trying to finish the work for five days.
Rule-5
If there is While in the sentence, there will be ing next to verb (V+ing). But there is subject after while, the sentence will be in continuous tense.
Example
I saw him while (work) working in the field.
I saw him while he (work) was working in the field.
Rule-6
If there is lest in the sentence, there will be Sub+should / might +V1--
Example
Walk fast lest you (miss) should miss the train.
Rule-7
If there is It is high time / It is long time/ It is time in the sentence, there will be To + V1--- . But there is Subject after It is high time/It is long time/ It is time in the sentence, there will be past form of verb (V2)
Example
It is time (go) to go there.
it is high time we (finish) finished our duty.
Rule-8
There should be ing (V+ing) after prepositions without To .
Example
Thank you for (give) giving me the pen.
Rule-9
If there are with a view to / look forward to / get used to / with an eye to/being accustomed to/ being used to/ admit to/ confessed to in the sentence, there will be ing next to verb (V+ing).
Example
He came here with a view to (take) taking coffee.
Rule-10
If there is as if / as though in the sentence, after as if / as though there will be like the structure in the below.
Sub+ present tense ---+ as if / as though + Sub + past indefinite tense.
Sub+ past tense ---+ as if / as though + Sub + past perfect tense.
Example
He speaks as if he (know) knew nothing.
He acted as though he (do) had done the work.
Rule-11
If ther are two verbs side by side, there will be to before the 2nd verb or ing at the end of the 2nd verb.
Example
He wanted (do) to do the job.
She started (take) taking cofee.
Rule-12
If there is have/ has/ had/having/ to be/ being in the sentence , after them there will be past participle form of verb or V3.
Example
He has (do) done the work.
Rule-13
If there is can't help/ couldn't help/would you mind in the sentence , after them there will be ing of verb or V+ing.
Example
Would you mind (take) taking coffee?
Rule-14
If there is modal verb in the sentence , after them there will be present form of verb or V1.But there is be after modal verb, there will be past participle of verb or V3.
Example
He must (open) open the door.
The door must be (open)opened .
Rule-15
If the sentence is in the passive mood, the verb of the sentence will be past participle .
Example
It was (invent) invented over night.
Rule-16
If there is so that / in order that in the sentence, there will be Subject+ can / could + V1---
Example
He reads book so that he (gain) can gain knowledge.
Rule-17
If a sentence contains just, just now, already, yet, ever, lately, recently, etc.,The verb will be in the present perfect tense.
Example
I already (do) have done the work.
Rule-18
If the first part of after is in past indefinite tense, the next part will be past perfect tense.
Example
The doctor came after the patient (die) had died.
Rule-19
If the first part of before is in past perfect tense, the next part will be past indefinite tense.
Example
The patient (die) had died after the doctor came .
Rule-20
If the 1st part of the sentence starts with wish/ fancey/ would that , there will be Subject+ were+Noun+---/ Subject+ could+V1--.
I wish I (be) were a king.