现在完成时难点瞬间动词转换成延续性动词

现在完成时之瞬间动词转变成延续性动词

for\since:

for+一段时间，常常可以发现for+数字

，for three months for a long time for many years

Since+时间点，常常可以发现

a. since+月份，年份，表示时间的几点

since September since 1990 since 7 o’clock

b. since+一段时间+ago；

since two years ago since ten months ago

+ last+....

since last month since last year

现在完成时的结构式has\have done 请注意第三人称：she\he\人名...+has

当句子为肯定句，且居中出现for\since的时候，句中的时态要用现在完成时，且句中的动词要用延续性动词。

当句子为否定句时，句中的动词可以为瞬间动词，表示某个动作不发生的状态已经持续了......

在有for\since的现在完成时的从句中，如何将瞬间动词转换成延续性动词

以borrow——keep为例子

They borrowed it last week.

They have kept it since last week.

分析：

我们已经知道现在完成时的标志就是has\have done，因此第一步就是看主语，主语时They，我们选择have done。

因为borrow——keep.而keep——过去分词：kept，因此，have borrowed就需要改成have kept. Since后面只能接时间点，而last week就是一个时间点，因此，since后面直接填写last week。常考的瞬间动词：

原形过去式

过去分词动词原形动词过去分词die--be dead die died

died be dead been dead borrow--keep borrow borrowed borrowed keep kept leave--be away from

buy--have buy bought

bought have had

begin--be(on) begin began

begun be been

join--be a member of

be in join joined joined be in been in become--be become became become be been

Open\close--be open open opened opened be open been open

finish--be over finish finished

finished be over been over

put on--wear put put

put wear worn

catch a cold--have a cold catch caught caught have had

go to--be in go went

gone be in been in

get to know--know get got got know known

Arrive in\at--be in arrive arrived

arrived be in been in

Move\come\get to--be in

go out--be out go went gone

be been

Move\come\get to--be in

be in been in

举例

Mr. Smith came to this school in September.

Mr. Smith ___has____ ____been____ at this achool_____since___ September.

分析：

1, come--came--come

2, 本来应该是填写has come to，但是come to要转换成be in

3, 而be的过去分词为been因此我们填写的内容为has been in

4，因为句子中已经有了at，所以我们只需要填写has been