modal verbs CT

It is necessary/essential / important

• S + Must +V₀

• S + Must +have + V3ed

• S + should +V₀

• S + should +have V3/ed

It’s certain that/I am sure that + S +V (present /future)    

• S + Must +V₀

• S + Must +have v3/ed

• S + should +V₀

• S + should +have V3/ed

It’s certain that /I am sure that+   V_2/ed                  

• S + Must +V₀

• S + Must +have V3/ed

• S + should +V₀

• S + should +have V3/ed

S + be not allowed to +V₀

• S + Must +V₀

• S + Must +have V3/ed

• S + Mustn't +V₀

• S + should +V₀

It wasn’t     necessary

• S + Must +V₀

• S +Mustn’t +V₀              

• S +needn’t +have +V_{3/ ed}         

• S +needn’t + V₀

It isn’t       necessary

• S + Must +V₀

• S +Mustn’t +V₀              

• S +needn’t +have +V_{3/ ed}         

• S +needn’t + V₀

It’s a good idea

• S + Must +V₀

• S +Mustn’t +V₀              

• S + should +V₀

• S + should +have V3/ed

It was wrong of

• S + Must +V₀

• S +Mustn’t +V₀              

• S + should +V₀

• S +Should/ shouldn’t + have + V_3/ed                            

Perhaps/It is possible that     +S +V₂ /ed                  

• S + Must +V₀

• S +Mustn’t +V₀              

• S + may /might + V₀

• S + may / might (not) +have + V_3/ed