The negative of should is should not. It is usual to join these two words together: shouldn’t. Should has a lot of uses that do not fit easily into one pattern. The best way to approach this word is to take note of each use as you hear it. Distant possibility: If you should see him, tell him I’ve left.(Kdybys ho měl náhodou vidět, řekni mu, že jsem odešel.) Probability: He should be here soon. Prediction: I should be perfectly happy if I won a million pounds. After verbs such as command, order, insist (nařídit, přikázat, poručit, trvat na něčem): He insisted that the contract should be signed immediately. (Trval na tom, aby byla smlouva ihned podepsána.) After some adjectives such as important, vital: (nezbytný, nutný, podstatný, důležitý): It’s important that they should study hard for the exam. Talking about obligation or duties(měl bych, měl bys): He should see his mother more often. Asking for / Giving advice: What should I do? I think you should call her.