8B Unit 1 Past and present Grammar 现在完成时 现在完成时用来表示之前已发生或完成的动作或状态,但它的影响现在还存在;也可表示持续到现在的动作或状态
其构成: have (has) +过去分词
规则变化的过去分词与过去式的变化一样,在动词词尾加 ed; 不规则变化的过去分词见不规则动词表,需要同学记忆
现以 see the film 为例将现在完成时的肯定句, 否定句和疑问句列表如下: 肯定句:I/You/We/They have seen the film
He/She /It has seen the film
否定句:I/You/We/They have not/ haven’t seen the film
He/ She/It has not/hasn’t seen the film
疑问句:Have I/you/they seen the film
Yes, you/ we/I/they have
No, you/ we/I/they haven’t
Has he/she/it seen the film
Yes, he/ she/ it has
No, he/ she/ it hasn’t
二、用法:现在完成时既涉及过去,又联系现在
用法一:表示过去发生或已经完成的某一动作对现在造成的影响或结果
常与 just(刚刚),already(已经),never(从来没有),ever(曾经),before(以前),yet(仍然),once(一次),twice(两次),many times(很多次),how many times(多少次),so far(迄今为止),during the past(last)three years(最近三年来)等连用
※ 副词的位置:①just 常用于肯定句中,放在 have / h