Right form of Verbs:

Rules of Right Form

1. Action word takes 's', 'es' when its subject is third person singular. As: The girl plays Ludo. Tom likes Jennifer. She goes to school. Rahima sings a sweet song. Lubna loves none. Kazal loves Salimullah. Bulbul asks his mother about her father. Masud reads well. Mina tries to establish a teaching centre.

2. Present Indefinite Tense uses for any kinds of truth. As: Oil floats on water. The sun rises in the east. The earth is round. The earth moves round the sun. Rainbow contains seven colours.

3. The presence of the following word indicates present indefinite. They are "regularly, sometimes, often, generally, daily, everyday, occasionally, usually, normally." As: When does Mr. Rahim take his food normally. A good student prepares his lessons regularly. Sometimes she goes there. He often comes here. She always makes a noise in the class.

4. Do, does, or did must create to make questions or negative in auxiliary verb-less sentence. As: The boy does not work hard. Did Karim come home yesterday.

5. To be verb uses before subject while wh -word "Who, what, when, where, which , whose, why, how" placing beginning of the sentence. As: Why does Mrs. Bill look so happy? What do you want? What would you like to have?

6. Present continuous tense places for progressive (continue) action at present. As: Bristy is singing a song. Ety is watching TV at the moment. I am writing blog now.

7. For 'Have' verb past participle should place in the sentence. As: She has done the dancing. They have made him captain.

8. The following words also follow present perfect tense. They are: just, just now, already, yet, ever, lately, recently. As : I have met her recently. Have you ever been to the zoo? They have gone out just now.
9. With some phrases in sentences , like : yesterday, ago, long since, last night. As: She left the school last year. I went home yesterday. She saw me long ago.
10. Sentence with some phrases like, no sooner had --- than, scarcely had when, hardly had, before etc contain past perfect at first portion of sentence and next part contain past Indefinite. As: No sooner had he seen the police than he ran away.
11. Sentences containing since in the first portion refers present indefinite replaces second portion as past Indefinite. As: It is many years since I came to Dhaka. Thirty three years have passed since my father Abdur Rob died. Seven months have past since my mother Safia Khatun departed the world.
12. Sentences containing since in the first portion if refers past indefinite replaces second portion as past perfect. As: It was many years since they had first met. It was long since I had seen her last.
13. Past perfect tense uses previously 'before' and later on 'after': As: The patient had died  before the doctor came. The doctor died after the patient had come. We left home after the beggar had come.
14. In a sentence, if there are two simple present verb, the second verb turns into either 'continuous' or takes 'infinity to': As: I saw him going or I saw him to go. I don't want to leave this place. or , I do not want leaving this place.
15. The following word like 'had better, had rather, would better, would rather, let, must, need, dare takes present indefinite. As: You had better go home. I shall not let you enter the classroom.
16. The portion 'would that ' takes 'could' after the subject: As: Would that I could go to college.
17. The principal verb of 'to be' and 'having' takes past participle. As: She ran away having  taken the memory. The principal desired the notice to be hung.
18. Preceding the given verbs mind , worth, without, past, cannot help, could not help with a view to, look forward to, would you mind, get used to and preposition uses then 'ing' is added verb. As: I went to the factory with a view to earning there. She never thought of going to cinema.
19. The next verb becomes past indefinite if the sentences contain 'it is high time' 'it is time, ' wish, fancy etc. remains in a sentence. As: It is high time he changed his habit. I wish I sang a song. I fancy I turned pale.
20. To be verb becomes 'were or past indefinite' when we notice 'as though, as if, wish' in the sentence. As: I wish I were a king. He talks as if he were a leader. He speaks as though he knew everything. She proceeded as though I had not spoken.
21. Every, one of , each follows singular verb. As: One of the boys was absent yesterday. Everybody loves flower.
22.Modal auxiliary follows present simple principal verb. As: You may come tomorrow. I can do the the work. One should take care of one's health.
23. Would should placed before main verb when next day,week, month, year etc. take place in the sentence. As: He said that he would go home the next day.
24. Auxiliary verb (am, is , are, was, were) always follows a past or present participles. As: The book was stolen. They were playing.
25. First conditional follows the structure: If + present indefinite + Future indefinite. As: If he works hard, he will shine. If you run in the rain, you will catch cold. I shall go out if it rains.
26. Second conditional follows the structure: If + past indefinite + future in past (would /might /could). As: If he came , I would go. If I had a typewriter I would type. If he wanted , I would help him.
27. Third conditional follows the structure: If + Past perfect + future in past perfect. As: If I had seen him, I might have told him.
28. If the sentence begins with this structure 'Had + Subject + Past Participle' then the rest part begins with perfect conditional. It indicates would have, could have, might have in the rest part of the sentence. As: Had I been a king, I would have helped the landless.
Had I possessed vast property , I would have established a university.
29. Unreal past receives unreal verb and 2nd part contains might/ would /could, or might/ would /could have: As: If I were a bird, I would fly. If I were a bird would have flown. If I were you I would not do this. If I were a king I would help the poor.
30. Action starts ago but still continuing now. In these case present perfect continuous uses. As: I have been reading for three hours. I have been leaving in this house for ten years. It has been raining since morning.
31. Have, has, had, get, got, etc. uses as causative verb follows past participle. As: I got the work done by him. I had my rice cooked.
32. Lest follows should/would after subject in the sentence. As: He ran fast lest he should miss the train.
33. Just, after  follows  present participle (verb +ing)  but while follows continuous tense. As: While walking in the garden, a snake bit him. After walking he went to rest. While he was walking on the bank of the river, he saw the sunset scene.
34. Subject and verbs follows the number. As: The colour of his eye is black. The players in the  field are strong.
35. Unit follows singular number:As: Fifty miles is a long way.
36. The word 'there' receives singular or plural verb  according to the contents.
As: There is a high school in a village. There are two high schools in our village.

** For more details look Tense