guess + noun
Can you guess her age?

guess + at + noun
It’s difficult to guess at the figures.

guess + adverb
He had to choose one, and he guessed correctly.

guess + wh- clause
It’s not hard to guess where he went.

guess + clause
He guessed she was at home.

guess + that + clause
He guessed that she was at home.

adjective + to + guess
It’s difficult to guess the outcome.