He must know/ He must have known/He must have to know/He must have had to know...

Question

Hello.What is the difference between these sentences?- He must know the entry code, too.- He must have known the entry code, too.- He must have to know the entry code too.- He must have had to know the entry code too.I would be very grateful for all your help about this thread.Thanks.

CalifJim · Accepted Answer

1 He must know the entry code, too.
2 He must have known the entry code, too.
3 He must have to know the entry code too.
4 He must have had to know the entry code too.

1 The only logical conclusion is that he too knows the entry code. [present]

2 The only logical conclusion is that he too knew the entry code. [past]
3 The only logical conclusion is that he too is required to know the entry code. [present]

4 The only logical conclusion is that he too was required to know the entry code. [past]

In 1 you deduce that he knows something on the basis of what you know or are observing now.

In 2 you deduce that he knew something on the basis of what you knew or observed earlier.

In 3 you deduce that he has some obligation on the basis of what you know or are observing now.
In 4 you deduce that he had some obligation on the basis of what you knew of observed earlier.

CJ

BarbaraPA · Answer

CJ, I would have written #4 as "He must have had to have known." Am I nuts, or are the two versions each okay but saying different things?

CalifJim · Answer

The traditional grammar mavens say that the "have" should be used only on the first of two verbs in a row like that, and that adding the second "have" does nothing to change the meaning, but I think we all occasionally throw in the extra "have", just to be sure. I think it's just a reflex action of the language machinery in our heads that wants the tenses to match up neatly.

Personally, I accept either version, and I don't try to "dig too deep" into the subtle differences in meaning, if any. It hurts my brain.

This is in the same category as those countless discussions of would like / would have liked / to / to have, where there are four combinations, and some people claim to sense four different meanings, which I find hard to believe, but maybe I'm slow when it comes to would have's.

(If you are nuts, it's for different reasons.

)

CJ

BarbaraPA · Answer

Thank you. That makes sense (and I agree about those combinations and permutations... without much nuance in meaning). In honor of your kind reply, I will endeavor to not split any infinitives today. I mean, not to split... oh you know...

CalifJim(If you are nuts, it's for different reasons. )

Fair enough!

Anonymous · Answer

Try to read the sentence in a loud voice.
The grammar is incorrect if it is not pleasing to the ears.

He must know/ He must have known/He must have to know/He must have had to know...

Top answer

Get the Weekly English Kit 📬

Related Questions