Yes, I agree with you.
Normally, yes, but I think John is talking about this example from the lesson:
Tu aurais vu sa tête quand je suis apparu devant lui !
You should have seen his face when I appeared in front of him!
In this case, "should have" does not mean "you ought to have", so using devoir would be an anglicism. The meaning is more like "if you had seen his face!".
In French, this could be either:
Si tu avais vu sa tête or
Tu aurais vu sa tête (using the conditional instead of si)
Sign in to submit your answer
Don't have an account yet? Join today
Test your French to the CEFR standard