Shall
“Shall” is used to indicate future action. It is most commonly used in sentences with “I” or “we,” and is often found in suggestions, such as “Shall we go?” “Shall” is also frequently used in promises or voluntary actions. In formal English, the use of “shall” to describe future events often expresses inevitability or predestination. “Shall” is much more commonly heard in British English than in American English; Americans prefer to use other forms, although they do sometimes use “shall” in suggestions or formalized language.
Examples:
Shall I help you? (suggestion)
I shall never forget where I came from. (promise)
He shall become our next king. (predestination)
I’m afraid Mr. Smith shall become our new director. (inevitability)
Shall এর ব্যবহার:
1. ভবিষ্যত ঘটনা(Future incident) বুঝাতে: I/We এর সাথে shall হয় ।
যেমন- I/We shall do the work.
2. Command, threat, determination(আদেশ,হুমকি,দৃঢ় প্রতিজ্ঞা)বুঝাতে: 2nd, 3rd Person এর সাথে shall
ব্যবহৃত হয় যেমন- You shall carry out my order.
The weak shall be given equal rights.
Should
“Should” is most commonly used to make recommendations or give advice. It can also be used to express obligation as well as expectation.
Examples:
When you go to Berlin, you should visit the palaces in Potsdam.( recommendation)
You should focus more on your family and less on work.( advice)
I really should be in the office by 7:00 AM.( obligation)
By now, they should already be in Dubai. (expectation)
Should এর ব্যবহার:
1. Obligation/duty/advice (বাধ্যবাধকতা/কর্তব্য/উপদেশ)বুঝাতে: We should obey our Parents.(Duty)
You should stop smoking.(Advice)
2. আশংকা বুঝাতে Purpose clause এ lest এরপরে should বসে ।যেমন- He walked fast lest he should miss the train.
3. অতীতের Obligation বুঝাতে: You should have read sincerely.(Past)
এই লেকচারের পরের পেইজে যেতে নিচের 
…. তে ক্লিক কর।