1. He is often late for school.
2. He isn't often late for school.
3. He often isn't late for school.
(What about the position of the frequency adverb? Are both #2 and #3 grammatical?)
All three are grammatically correct, but #3 is not used commonly. #2 has the more common placement of the adverb.
The position of the frequency adverb in a sentence is important for clarity and grammatical correctness. In general, frequency adverbs like "often" are placed before the main verb in a sentence.
Let's analyze each of the provided sentences:
1. He is often late for school.
In this sentence, the frequency adverb "often" is placed before the verb "late." This is the standard word order for frequency adverbs in English. Therefore, this sentence is grammatically correct.
2. He isn't often late for school.
In this sentence, the negative form "isn't" (the contraction of "is not") is used before the frequency adverb "often." While this positioning may sound slightly less common in everyday conversation, it is still grammatically correct. The negative form "isn't" separates the verb "is" and the adverb "often."
3. He often isn't late for school.
In this sentence, the frequency adverb "often" is placed before the negative form "isn't." This positioning, although less common, is still grammatically correct. The adverb "often" modifies the verb phrase "isn't late."
So, both sentence #2 and sentence #3 are grammatically correct, although the positioning of the frequency adverb in sentence #3 may sound less common in everyday conversation.