油尺现在完成时态常与一些时间状语连用

2021年1月13日发(作者：羊宗道)
现在完成时
1. 构成方法
have/has +动词的过去分词
现在完成时的否定式是在have/has的后面直接加not；
变为疑问句时，要将have/has提到主语之前。
2. 现在完成时态常与一些时间状语连用：
yet, already, just, before, ever, never, recently, so far, till/until, up to now, in the
past few years, etc.
含义 用法 例句

already 已经 肯定句 I have already finished my homework.

yet 尚未；还未 否定句、疑He has not heard from her yet.
问句 Has Mr Wang arrived yet?

just 刚刚 肯定句 She has just cleaned the kitchen.

never 从未 否定句
She’s never talked to a foreigner.

ever 曾经 Have you ever visited the Great Wall?
This is the best book I have ever read.
before 以前，之前 Have you been to the USA before?
3. since四种用法：
a) since + 过去一个时间点（1980, March)
I have been here since 1989.
b) since + 一段时间 + ago
I have been here since five months ago.
c) since + 从句
Great change have taken place since you left.
d) It is + 一段时间 + since 从句 （过去时）
It is twelve years since I became a student.
4. For 引导的表示一段时间的状语
They have been in Canada for ten years.
My brother has kept this book for 5 weeks. (特殊疑问句)
→ How long has your brother kept this book?
5. 现在完成时与一般过去时的区别
一般过去时的时间状语：yesterday , last week, two days ago, in 2000, just
now …
6. have gone to, have been to, have been in
a. Jim has gone to London with his family.
(He is on his way or in London now)
b. Jim has been to London before.
(He is back now.)
c. Jim has been in London for two weeks.