1. He had stayed with his old master for long. (For 5 month, he has lived with his new master.)

2. They had been together for such a long time.

3. He had stayed with his old master together for ages.

4. He had been with his old master long.
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Will you check the expressions? Are they good? If there are any errors, correct them, please? Thank you.

1. He had stayed with his old master for a long time.

For 5 months, he has lived with his new master.

2. They had been together for such a long time.

3. He stayed with his old master for ages.

4. He had been with his old master a long time.