1. It's not actually raining now.

2. It's not raining now actually.
3. Actually it's not raining now.
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Which one is grammatical? Where should we put 'actually' in the sentence?

#2 is a bit awkward, perhaps. I'd put a comma in the sentence: "It's not raining now, actually." We might say that colloquially, in casual conversation, but not in formal writing. #1 and #3 are better, but I'd use a comma in #3, too: "Actually, it's not raining now."

All three sentences are grammatically correct, but they have slightly different word order and emphasis.

1. "It's not actually raining now."
2. "It's not raining now actually."
3. "Actually, it's not raining now."

The placement of 'actually' depends on the intended meaning and emphasis.

In the first sentence, 'actually' is placed after the verb 'raining,' indicating that the statement contradicts what might be expected. This sentence emphasizes that contrary to belief or expectation, it is not raining.

In the second sentence, 'actually' is placed before 'now,' which can express surprise or correction. The addition of 'actually' gives a sense of surprise or correcting a mistaken assumption about the current weather.

In the third sentence, 'actually' is placed at the beginning, often followed by a comma. This placement is commonly used to introduce a contrast or to emphasize a point. The emphasis is on 'actually,' drawing attention to the fact that it is not raining, despite what might be thought or said.

Therefore, all three sentences are grammatically correct, but your choice would depend on the intended meaning and emphasis you want to convey.