Use of Modals: Should | Would

You should find her in the play-ground. - Probability
You should take care of your health. - Advice
You should take care of your briefcase. - Responsibility
You should complete your work every day, - Mild command
He should be reading now. - Probability
He should be worried about me. - Presumption
They should be anxious about us. - Presumption

 2.  Conditional sentences में lest के साथ हमेशा should का प्रयोग किया जाता है। यह एक Important use है। जैसे:
Move fast lest you should miss the bus. जल्दी चलो कहीं तुम्हारी बस न छूट जाये।
Work hard lest you should fail. मेहनत, करो, कहीं ऐसा न हो कि तुम फेल हो जाओ।
Lest का अर्थ कहीं ऐसा न हो कि होता है।

 3.  Should का प्रयोग purpose व्यक्त करने हेतु किया जाता है, तब वह may व्यक्त करते हुए किया जाता है, तब वह एवं might के अर्थ को समान रखता है। जैसे:
I taught her so that she should pass. (She might pass.)
I scolded him so that he should work hard. (He might work hard.)

 4.  Should का Perfect Tense में प्रयोग इस तथ्य को स्पष्ट करता है कि जो कार्य जिस रूप में किया जाना चाहिये था, वह नहीं किया गया। जैसे:
He should have gone by morning bus. (but he didn't go.)
She should have informed me about the incident. (but she didn't inform me.)
Ramesh should have submitted the bills. (but he didn't submit.)

Would

 1.  Would का प्रयोग will की अपेक्षा अधिक polite request को बताता है। Request हेतु will की अपेक्षा would का प्रयोग अधिक मान्य है। Would का प्रयोग दूसरे की इच्छा (Willingness) जानने हेतु भी किया जाता है। जैसे:
Would you accompany me to the railway station? Polite request.
Would you send me an application form?
Would you sing at the concert tomorrow?

 2.  Would का प्रयोग likelihood, presumption,एवं probability को भी व्यक्त करता है। जैसे:
He would be in the field.
She would be in the club at this time.
She would be cooking now.
She would be about 80 now.

 3.  Rather के साथ would का प्रयोग preference (प्राथमिकता) को व्यक्त करता है। जैसे:
I would rather rest now.
I would rather study than see a movie.
I would rather play than rest now.

 4.  Wish के साथ will का प्रयोग नहीं किया जाता है। wish के साथ would का प्रयोग strong desire/willingness स्पष्ट करता है। जैसे:
I wish you would fight this election.
I wish you would support her fully.
I wish they would agree to this proposal.

 5.  Unreal (काल्पनिक) परिस्थितियों को व्यक्त करने हेतु भी would का प्रयोग conditional sentences में किया जाता है। जैसे:
If I had one crore rupees, I would donate fifty lacs to the trust.
If I had wings I would fly to Europe.
If I were the king, I would make you any chief adviser.
If a tiger came into the room, what would you do?

 6.  Conditional sentences में past perfect के sentences में would का प्रयोग किसी कार्य के past में न होने को व्यक्त करता है। जैसे:
If he had come to me, I would have given him a job. (He didn't come.)
यदि वह मेरे पास आता तो मैं उसे नौकरी दे देता।

 
If she had asked me, I would have helped her. (But she didn't ask me.)
यदि वह मुझे कहती तो मैं उसकी सहायता करता।

 7.  Would Will' का past है, Direct से Indirect narration में परिवर्तन करते समय reporting verb past में होने पर will को would में बदलते हैं। जैसे:
He told me that he would go to Jaipur the next day.
He told me that she would not agree to the proposal.