have vs should

have

verb
  • To be affected by an occurrence. (Used in supplying a topic that is not a verb argument.) 

  • To be afflicted with, suffer from. 

  • To consider a court proceeding that has been completed; to begin deliberations on a case. 

  • To believe, buy, be taken in by. 

  • To feel or be (especially painfully) aware of. 

  • To obtain. 

  • To include as a part, ingredient, or feature. 

  • See have to. 

  • To defeat in a fight; take. 

  • To accept as a romantic partner. 

  • To undertake or perform (an action or activity). 

  • Used to state the existence or presence of someone in a specified relationship with the subject. 

  • To cause to, by a command, request or invitation. 

  • To cause to be. 

  • To be able to speak (a language). 

  • To hold, as something at someone's disposal. 

  • Used as an interrogative verb before a pronoun to form a tag question, echoing a previous use of 'have' as an auxiliary verb or, in certain cases, main verb. (For further discussion, see the appendix English tag questions.) 

  • To trick, to deceive. 

  • To experience, go through, undergo. 

  • To allow; to tolerate. 

  • To depict as being. 

  • To inflict punishment or retribution on. 

  • To make an observation of (a bird species). 

  • To possess, own. 

  • To engage in sexual intercourse with. 

  • To get a reading, measurement, or result from an instrument or calculation. 

  • To consume or use up (a particular substance or resource, especially food or drink). 

  • Used in forming the perfect aspect. 

  • To host someone; to take in as a guest. 

  • To be scheduled to attend, undertake or participate in. 

  • To give birth to. 

noun
  • One who has some (contextually specified) thing. 

  • A wealthy or privileged person. 

  • A fraud or deception; something misleading. 

should

verb
  • Used to give advice or opinion that an action is, or would have been, beneficial or desirable. 

  • Will be likely to (become or do something); indicates a degree of possibility or probability that the stated thing will happen or be true in the future. 

  • Indicates that something is expected to have happened or to be the case now. 

  • Used to express a conditional outcome. 

  • With verbs such as 'see' or 'hear', usually in the second person, used to point out something remarkable in either a good or bad way. 

  • To make a statement of what ought to be true, as opposed to reality. 

  • Used to impart a tentative, conjectural or polite nuance. 

  • Used to express what the speaker would do in another person's situation, as a means of giving a suggestion or recommendation. 

  • Simple past tense of shall. 

  • In questions, asks what is correct, proper, desirable, etc. 

  • Used to issue an instruction (traditionally seen as carrying less force of authority than alternatives such as 'shall' or 'must'). 

  • Used to form a variant of the present subjunctive, expressing a state or action that is hypothetical, potential, mandated, etc. 

noun
  • Something that ought to be the case as opposed to already being the case. 

How often have the words have and should occurred in a corpus of books? (source: Google Ngram Viewer )