1. Oh, this is him.

- Right.

2. Oh, this is he.
-Right.
(Which one is right or grammatical?)
English - Writeacher, Monday, June 25, 2012 at 9:57am
#2 is the grammatically correct one.

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Thank you.

Q1) Can we use "This is him." in a colloquial speech?

Q2)
3. I think the person to be he.
4. I think the person to be him.

(In this case, which one is correct?)

Q1) Although "This is him," is often used, it is still wrong. I would not say it is colloquial.

Q2) Both are awkward, but 3 is correct. A better way is "I think the person is he."