Question

1. He wants to be a singer in the future.

2. He was a lawyer in the past.

3. He is a doctor in the present.

4. He is a doctor at present.

5. He is a doctor at the moment.

6. He is a doctor currently.

7. He is a doctor now.

8. He is a doctor at the present.

(From #3 to #8, there are similar sentences. Are they grammatical? Which expressions should I use? Are they all the same in meaning?)

Answer 1

3-8 all mean the same thing, yes, and all are grammatically correct.

I wouldn't use #3. I'd use #8 with "at the present" or simply "at present" (#4) at the beginning of the sentence.