Which conjunction correctly completes this sentence: 'He sees the online world as a tool, ______ helps both information collection and distribution'?
答案解析
Core concept: Grammar (relative clauses).
Key analysis: Non-restrictive clause requires 'which' (A) as the relative pronoun. 'That' (B) cannot be used in non-restrictive clauses. 'Where' (C) refers to places, and 'when' (D) refers to time, both inappropriate for describing a tool.
Common mistake: Confusing restrictive and non-restrictive clause markers.
正确答案：A