Classify the following into acids and bases according to Lewis concept:
`S^(2-) , H^(+), OH^(-) , BF_3 , Ni^(2+), F^-`

Explanation

To classify the given species into acids and bases according to the Lewis concept, we need to identify which species can accept electrons (Lewis acids) and which can donate electrons (Lewis bases).

### Step-by-Step Solution:

1. **Identify Lewis Acids and Bases:**
- **Lewis Acid:** A species that can accept an electron pair.
- **Lewis Base:** A species that can donate an electron pair.

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