Guess/guess at

Only the first sentence is correct.

Thanks, so when should we use "guess at"?

trolleyThanks, so when should we use "guess at"?

'guess' is enough; 'at' is not necessary.

Thanks for your reply:)
However, when I check on Longman dictionary, it says:

"guess at
We can only guess at the cause of the crash."


So do you mean that "We can only guess the cause of the crash" is also acceptable?

I see no real difference between 'guess' and 'guess at', though I never use 'at'. It seems to me to be one of those recent additions to the language of some people that is unnecessary but does no harm.

If you want to use extra words, then 'make a guess at' works. We need 'at' there.

Thank you so much fivejedjon:)

trolleyCan you guess at the value of this ring?

Can you make a guess, any guess, right or wrong, at the value of this ring?

trolleyCan you guess the value of this ring?

Can you correctly state the value of this ring?

Also, the same meaning as for "guess at".

CJ

Thanks CalifJim:)
You guys have helped me to understand more!

trolleyThanks CalifJim

You're welcome. I think most speakers of Portuguese understand some Spanish, so maybe I should have told you the Spanish equivalents and it would have worked. However, I don't know if Portuguese has both of these words.

guess at is more like adivinar; guess can be adivinar or atinar

Wow it is nice of you to try to include other language to facilitate my understanding:)
Yet, I am not a Portuguese nor can I understand Spanish. I come from Hong Kong so my native language will be Chinese.