1. Sometimes I'm sad.
2. I am sometimes sad.
3. I am sad sometimes.
4. Sometimes I feel sad.
5. I sometimes feel sad.
6. I feel sad sometimes.
(Are they all grammatical?)
2. I am sometimes sad.
3. I am sad sometimes.
4. Sometimes I feel sad.
5. I sometimes feel sad.
6. I feel sad sometimes.
(Are they all grammatical?)