has been doing 用法详解
掌握现在完成进行时的核心要点
什么是 has been doing？
has been doing 是英语中“现在完成进行时”（Present Perfect Continuous）的第三人称单数形式，用于描述从过去某一时间开始、一直持续到现在（可能仍在继续）的动作或状态。
其基本结构为：
- 肯定句：主语 + has/have + been + 动词-ing
- 否定句：主语 + has/have + not + been + 动词-ing
- 疑问句：Has/Have + 主语 + been + 动词-ing?
注意：has been doing 用于第三人称单数（he, she, it, Tom, the cat 等），而 have been doing 用于其他人称（I, you, we, they 等）。
典型使用场景
- 强调动作的持续性：表示某事从过去开始，一直持续到现在，可能还会继续。
She has been studying English for three hours.
- 解释当前状态的原因：说明为什么现在看起来累、湿、高兴等。
He has been running — that’s why he’s out of breath.
- 表达最近反复发生的动作（带有情绪色彩）
Lately, she has been calling me every day.
与 has done 的区别
很多人混淆 has been doing 和 has done（现在完成时）。关键区别在于：
has done 强调结果或已完成的动作。has been doing 强调过程或持续进行的动作。
I have written three letters.（三封信已写完）
I have been writing letters all morning.（整个上午都在写信，可能还没写完）
常见错误提醒
⚠️ 并非所有动词都能用于进行时！以下动词通常不用 has been doing 结构：
- 表示状态的动词：know, believe, understand, love, hate, belong, seem 等。
❌ She has been knowing the answer.
✅ She has known the answer.
小练习（自测）
判断下列句子是否正确：
- He has been working here since 2020. ✅
- They has been waiting for the bus. ❌（应为 have been）
- She has been feeling tired lately. ✅（feel 在此表示“感觉状态”，但口语中常用于进行时）