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যেসব মৌলিক কণিকার স্পিনের মান n+১/২ (যেখানে n একটি অঋণাত্মক পূর্ণসংখ্যা) অর্থাৎ যারা পদার্থের গাঠনিক উপাদান (এরা বলের কণিকাসমূহ, যাদের স্পিনের মান ০, ১, বা ২, তাদের থেকে ভিন্ন), তাদের যেকোন দুইটি কখনো একই কোয়ান্টাম দশায় থাকতে পারে না --- এই নীতিকেই পাউলির বর্জন নীতি বলা হয়। সোজা কথায়, এমন দুইটি মৌলিক কণিকার অবস্থান এবং বেগ কখনো এক হবে না। অর্থাৎ, এমন দুটি কণিকাকে সংকীর্ণ থেকে সংকীর্ণতর কোন স্থানে আবদ্ধ করার চেষ্টা করলে (অর্থাৎ এদের অবস্থানের পার্থক্য কমিয়ে আনার চেষ্টা করলে) এরা আরো বেশী বেগে ছোটাছুটি করতে থাকবে (অর্থাৎ, এদের বেগের পার্থক্য বাড়তে থাকবে)।
যে সব মৌলিক কণা পাউলির বর্জন নীতি মেনে চলে, তাদের ফেরমিঅন বলে। ইলেকট্রন, প্রোটন ও নিউট্রন এরা সবাই ফেরমিঅন। আর যারা এই নীতি মানে না, তাদের বলে বোসন। ফোটন কণা একটি বোসন।
মহাবিশ্ব যদি পাউলির বর্জন নীতিকে উপেক্ষা করে তৈরি করা হতো, তাহলে ৩ টি করে কোয়ার্ক একত্রিত হয়ে একটি একক প্রোটন বা একক নিউট্রন তৈরি করতো না, এরা আবার
ইলেকট্রনের সাথে জোট বেধে একক পরমাণুও তৈরি করতো না। ফলে সমস্ত মহাবিশ্ব কোন সুনির্দিষ্ট আকৃতি না পেয়ে একটা জগাখিচুড়ি আকার ধারণ করত।
নীতিটিকে এর আবিষ্কারক ভোল্ফগাং পাউলির নামে নামকরণ করা হয়েছে।

Completing sentences:
Completing sentences means completing the incomplete sentence parts.
Some importants rules of completing sentence are given below:
1. If + conditional. Structure: If +sub+present form of main verb, sub+shall/will+present form of main verb:
a. If you come, I will go.
b. If it rains, I will not go to school.
c. If you works hard, you will prosper in life.
d. If Monika sings a song, I will dance.
2. If+sub+past form of main verb, sub+would/could/might.
a. If she came, I would go.
b. If I were a bird, I would fly in the sky.
c. If I were rich, I would help the poor.
d. If I had a lot of money, I would buy a car.
3. Unless means ‘if not’:
Examples: a. Unless you study hard, you will fail in the exam.
b. Unless he works hard, he will not prosper in life.
d. unless saon come, I will not go.
e. Unless you work hard, you will not/can not shine in life.
4. Till means ”to the time of/ up to/to the time when” :
a. wait here till I come back.
b. write till I come back.
c. I waited for her till he come back.
d. wait till I return.
e. Do not eat it till the doctor comes.
f. They worked in the field till the sun set.
5. Untill means not till:
a.I shall wait here untill he comes back.
b. We will not go to school untill the rain stops.
c. Wait here untill I return.
d. Do not go untill I come.
e. Wait untill the rain stops.
6. so that means ‘purpose’ , ‘in order to’.
Structure : Sub+verb+ so that+sub+may/can(present tense)/might/could(past tense)+ present form of verb +..
a. He works hard so that he can prosper/shine in life
b. The girl reads hard so that he may/can pass.
c. Della sells her hair so that she can buy a gift for her lover.
d. pray for me so that I can pass.
e. Eat good food so that you may keep your health fit.
f. He went to Tongi so that he might /could meet his mother.
g. We eat so that we may live.
7. So…….. that
a. The man is so old that he could not carry the load.
8. In order to/in order that:
a. He works hard in order to prosper in life.
b. In order to learn English, You have to learn tense well.
c. He works hard in order that he can prosper in life.
9. Though/although means ‘even if’ :
a. Though he is poor, he is honest.
b. Though he is rich, he is unhappy.
c. Although/though the man is poor , he is happy.
d. Although he works hard, he can not prosper in life.
10. And, but, or:
a. Do and eat.
b. Habib and sujon are friends.
c. Do or die.
d. Read or you will fail.
e. But for your help, I could fail.
f. Sandzida is tall but her sister is short.
11. As/since: a. As he was ill, he did not go to school.
b. Since you are ill, you can not go to school.
c. Since Maksodul is a good student, he made a good result.
d. As he was rich , he bought the house.
e. As he is short , he can not touch it.
12. Because of/on account of / wing to/due to:
a. I could not attend the class on account of /because of my illness.
b. I could not pay my tution fee because of(/on account of/ owing to/due to) my illness.
13. because: a.Everybody loves him because he is honest.
14. Relative pronoun [ who/which/that/whom/whose etc].
a. I know the man who came here.
b. This is the book which is yours.
c. I do not know what they want.
d. You will be glad to know that I have stood first in the class.
e. She knows that you will come again.
15. Without+ geround:
a. Without walking fast, you can not catch the train.
b. Without working hard, we can not prosper in life.
16. By+ geround: a. By working hard, we can prosper in life
b. By writing more, you can be a writer.
17. The place….. where/The time when:
a. The bus station is the place where buses stop and start from.
b. It is the place from where we can …
c. 10 pm is the time when the school starts.
18. so many/so much:
a. There were so many stars in the sky/people that we could not count.
b. He has so much money that he can buy the house.
c. There are so many stars in the sky that we can not count.
d. There are so many rats in our house, we can not count.
19. Whatever/Whenever:
a. Let him do whatever he likes.
b. Let him go whenever he wants.
20. While+ main verb+ing /while+past continuous tense:
a. While he was walking, he saw a snake.
21. Either ……. or, neither …….. nor.
a. Either I or he is responsible for the damage.
b. Neither he nor I am responsible for the damage.
22. Not only …… but also
(used for combined two same type of sentences.)
a. He is weak not only in English but also in Bengali.
23. No sooner ….. than; Scarecely ……… when; (or, before); Hardly …… when (or, before)
a. No sooner had he seen me than he ran away.
24. As soon as, so long as, as long as
a. As soon as I reached the school, the bell rang.
b. As long as he remains honest, he will succed.
a. The man worked so long as he cou