Which verb tense is predominantly used in the sentence: 'Technological changes have provided marketers with more choices but have increased risks.'?
答案解析
**Core Concept:** Present Perfect tense for actions continuing to the present.
**Answer Key:** B (The phrase 'have provided/have increased' uses Present Perfect to emphasize ongoing effects).
**Error Analysis:**
- A: Simple Past would require 'provided/increased' without 'have'.
- C/D: No future/past-before-past context exists here.
**Common Pitfall:** Mistaking Present Perfect for Simple Past due to past participle forms.
正确答案：B