Choose the correct verb form: If the patient ______ more attention, the complication could have been avoided.
答案解析
**Core Concept**: Grammar (third conditional).
**Analysis**: The sentence describes a past hypothetical situation.
- **Correct Answer (B)**: 'Had received' matches the structure 'If + past perfect, ... could have + past participle'.
- **Errors**:
- A. Simple past lacks hypothetical marker.
- C. Present tense contradicts past context.
- D. Future tense is illogical for past events.
**Key Point**: Third conditional requires past perfect in the 'if' clause.
正确答案：B