##### 现在时+动作状态
- 一般现在时
- 用来描述经常性, 习惯性的动作, 真理, 事实等
- 肯定句:主语 + 动词原形(第三人称单数加 -s)
- I work in an office.(我在办公室工作。)
- 否定句:主语 + do/does + not + 动词原形
- I do not (don't) work in an office.
- 疑问句:Do/Does + 主语 + 动词原形?
- Do I work in an office?
- 现在进行时
- 用来描述正在进行的动作
- 肯定句:主语 + am/is/are + 现在分词
- He is reading a book now.(他现在正在读书。)
- 否定句:主语 + am/is/are + not + 现在分词
- He is not (isn't) reading a book now.
- 疑问句:Am/Is/Are + 主语 + 现在分词?
- Is he reading a book now?
- 现在完成时
- 用来描述过去某个时间开始, 一直持续到现在的动作
- 肯定句:主语 + have/has + 过去分词
- I have finished my homework.(我已经完成作业。)
- 否定句:主语 + have/has + not + 过去分词
- I have not (haven't) finished my homework.
- 疑问句:Have/Has + 主语 + 过去分词?
- Have I finished my homework?
- 现在完成进行时
- 用来描述从过去开始, 一直持续到现在的动作, 并强调持续性
- 肯定句:主语 + have/has been + 现在分词
- She has been studying English for five years.(她已经学了五年英语。)
- 否定句:主语 + have/has not been + 现在分词
- They haven't been working on the project since last month.(他们上个月以来就没有在做这个项目了。)
- 疑问句:Have/Has + 主语 + been + 现在分词?
- Have you been practicing the piano for long?(你弹钢琴练习练了很久了吗?)