use of Must in present prefect tense

[Samie]

"From the beginnings of life the male must have realized he was physically stronger than a female."

in the above sentence i cant understand the use of must. is any body can clear it on me?

with thanks

[Haihao]

"In the beginning of human life, a male must have realized he was physically stronger than a female."

[Geo777]

Hi,

We use must have (done) for the past.
I've lost one of my gloves. I must have dropped it somewhere.
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Slow but sure.

[Mordant]

It just means that that has to be what happened.

He must have found it difficult.
He had to have found it difficult.
It must be a reality that he found it difficulty.

[Ahmeeeeeeeeeed]

a sort of deduction but you are completely sure

i can't find my keys, i must have forgotten them at my house.
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"There is no compulsion in religion; truly the right way has become clearly distinct from error....."

The qur'an 1:256

[Beeesneees]

Hi Ahmed,
"I can't find my keys, I must have left them at my house."
"I can;t find my keys, I must have forgotten them."

Don't combine the two as we would use 'forgotten them at'.
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Cheers m' dears!