1. A: Is Don in?
2. B: This is he.
3. B1: This is him.
(This is a telephone conversation. Can we use both 2and 3? Which one is grammatical?)
Although many people say "This is him," the only correct response is "This is he."
Both sentence 2 and sentence 3 are grammatically correct, but they have slightly different meanings and usages.
In sentence 2, "This is he," is a more formal and grammatically correct way of responding to the question "Is Don in?". It is considered more proper or polished, but it can also sound somewhat old-fashioned or stilted. This response confirms that the person speaking is indeed Don.
In sentence 3, "This is him," is a more informal and less strictly grammatical response. While it may be considered grammatically incorrect by some language purists, it is commonly used in informal speech and in everyday conversations. This response also confirms that the person speaking is Don.
In conclusion, either sentence can be used to answer the question "Is Don in?", but sentence 2 is more formal, while sentence 3 is more informal and commonly used in everyday speech. It ultimately depends on the level of formality desired in the conversation.