Sequence of Tenses
Latin verb sequor-এর সঙ্গে sequence শব্দটি সম্পর্কযুক্ত। Sequor শব্দটির ইংরেজি প্রতিশব্দ হচ্ছে follow. কাজেই বলা যায়, যে নিয়মানুসারে subordinate clause-এর verb principal/main clause-এর verb-কে অনুসরণ করে তা-ই হচ্ছে sequence of tenses.
Main Rules
1. Principal clause-এর verb present future tense-এ থাকলে subordinate বা dependent clause-এর verb যে কোন tense-এ হতে পারে। যেমন:
I know that he is successful.
I know that he was successful.
I know that he will be successful.
I shall know that he is successful.
I shall know that he was successful.
I shall know that he will be successful.
2. Principal clause-এ verb past tense-এ থাকলে subordinate dependent clause-এর verb সাধারণত corresponding (সঙ্গতিপূর্ণ) past tense-এ থাকে। যেমন:
I said that he was poor.
I said that he had been poor.
I said that he would be poor.
কিন্তু, subordinate clause universal truth habitual fact অথবা proverb প্রকাশ করলে তা present tense-এ থাকতে পারে। যেমন:
He said that all is well that ends well.
They believed that man is mortal.
3. Principal clause যে tense-এ থাকুক না কেন subordinate clause তুলনা (comparison) বুঝালে subordinate clause যে কোন tense-এ (present/past/future) থাকতে পারে। যেমন:
He helps me more than he helps you.
He helps me more than he helped you.
He helps me more than he will help you.
He helped me more than he helps you.
He helped me more than he helped you.
He helped me more than he will help you.
He will help me more than he helps you.
He will help me more than he will help you.
Some Other Rules
নিম্নে আমরা structure-সহ কিছু complex sentence উল্লেখ করছি যেগুলো থেকে principal clause ও subordinate clause-এর tense-সমূহের ব্যবহার জানা সম্ভব হবে।
Rule 1.
In case/provided (that)/providing (that)/if যুক্ত subordinate clause-টি present indefinite tense-এ হবে, যখন principal clause-টি present/future indefinite tense-এ হয়।
I want to stay at home in case/provided (that) providing (that)/if he comes.
In case you study well, you will pass.
Rule 2.
I wish/I like/I fancy/would that + subject + 'be' verb (were/could be) +....
I wish I were a poet.
I wish I could be a poet.
কিন্তু, I wish/I like/l fancy/would that/o that/oh that + subject + "be" verb ছাড়া অন্য verb থাকলে past form বা could + present form +....
I like I sang.
I like I could sing.
I wish I died.
I wish I could fly in the sky.
Would that he were alive today.
I fancy I turned a trifle pale.
Rule 3.
It is high time /It is time + subject + verb-past form +....
It is high time we did something for our country.
It is time you earned your livelihood.
Rule 4.
Main clause ( সাধারণত present indefinite tense/present perfect tense) + since + clause (past indefinite tense).
It is a long time since I saw you last.
Two years have passed since our father expired.
কিন্তু, Main clause (সাধারণত past indefinite tense) + since + clause (past perfect tense)
It was more than two years since they had left Bangladesh.
It was long since I had seen her last.
Rule 5.
Main clause (present tense) + as if/as though + clause (past indefinite tense; এক্ষেত্রে 'be' verb সবসময় were হয়)
He talks as if he were mad.
He pretends as though he knew everything.
কিন্তু, Main clause (past tense) + as if/as though + clause (past perfect tense)
He pretended as though he had known everything.
She proceeded as if I had not spoken.
Rule 6.
Main clause + lest + clause (subject + should/might + verb-এর base form +....)
They study hard lest they should fail.
I told her everything lest she should misunderstand me.
Rule 7.
Main clause + so that/in order that + subject + can/may (principal clause present tense হলে) অথবা, could/might (principal clause past tense হলে) + verb-এর base form +....
Drink clean water so that you can/may keep fit.
We worked hard in order that we could/might succeed.
Rule 8.
No sooner + had + subject + verb-এর past participle form... + than + subject + verb-এর past form....
No sooner had the bell rung than we entered the classroom.
No sooner had we reached the station than the train left.
No sooner had he got the news than he bur into tears.
Hardly + had + subject + verb-এর past participle form... + when + subject + verb-এর past form....
Hardly had we reached the station when the train left.
Hardly had the thief seen the police when he ran away.
Scarcely + had + subject + verb-এর past participle form... + when/before + subject + verb-এর past form....
Scarcely had they entered the stadium when/before the cricket match began.
Scarcely had the teacher entered the classroom when the students stood up.
Rule 9.
Main clause (present indefinite tense/future indefinite tense) + when/after + clause (present perfect tense).
I shall return you the book when/after I have finished reading it.
You can go to England when/after you have learnt English.
Rule 10.
Main clause (past perfect) + before + clause (past indefinite).
I had learnt my lessons before I went to bed.
Main clause (past indefinite) +after+ clause (past perfect)
They shone in life after they had worked hard.
Rule 11.
Main clause (past indefinite - পরে সংঘটিত) + dependent clause (past perfect - পূর্বে সংঘটিত).
He said that he had visited the zoo.
We knew that they had already reached there.
The ship had sailed away to the south until they arrived in cold grey seas.
Rule 12.
If clause (present indefinite), + main clause (future indefinite tense).
If it rains, I shall not go out.
If he does not come, I'll go to his house.
Rule 13.
If clause (past indefinite), + main clause (subject + would/could/ might + (not) + verb-এর base form).
If he worked hard, he would/could/might succeed.
If I were a rich man, I would/could/might set up a school.
Or,
Were I a rich man, I would/could/might set up a school.
If I had a lot of money, I would/could/might help the poor.
Or, Had I a lot of money, I would/could/might help the poor.
Note: Had + subject = If + subject + had এবং were + subject = if + subject + were.
Rule 14.
If clause (past perfect), + main clause {perfect conditional = subject + would/could/might (not) + have + verb-past participle form}.
If you had studied hard, you would/could/might have passed the exam.
Had I known it, I would/could/might have told you.
