can vs should

can

verb
  • Used with verbs of perception. 

  • To have the potential to; be possible. 

  • To cover (the fuel element in a nuclear reactor) with a protective cover. 

  • May; to be permitted or enabled to. 

  • To discard, scrap or terminate (an idea, project, etc.). 

  • To fire or dismiss an employee. 

  • To shut up. 

  • To know how to; to be able to. 

  • To seal in a can. 

  • To hole the ball. 

  • To preserve by heating and sealing in a jar or can. 

  • The boss canned him for speaking out. 

noun
  • An ounce (or sometimes, two ounces) of marijuana. 

  • A protective cover for the fuel element in a nuclear reactor. 

  • Jail or prison. 

  • A more or less cylindrical vessel for liquids, usually of steel or aluminium, but sometimes of plastic, and with a carrying handle over the top. 

  • A container used to carry and dispense water for plants (a watering can). 

  • Buttocks. 

  • Headphones. 

  • A cube-shaped buoy or marker used to denote a port-side lateral mark 

  • A chimney pot. 

  • A tin-plate canister, often cylindrical, for preserved foods such as fruit, meat, or fish. 

  • An E-meter used in Scientology auditing. 

should

verb
  • 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. 

  • 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. 

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

  • 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 can and should occurred in a corpus of books? (source: Google Ngram Viewer )