“作业没写完，就不能吃饭！”这句话，你小时候听过吗？虫子小时候，虫虫妈就像一台复读机：“你写完作业没有？”
写作业，影响到今晚吃饭的大事：这种“影响”，就是这节课要讲的「现在完成时」。
01. 意义：9个字
02. 结构
从上面3个例句，可见现在完成时的结构：
用 have 还是 has，就看主语是单数还是复数。原则是保持：主谓一致。
下面，根据提示，将下列句子变为现在完成时。
1）We ____________ (discuss) this issue a few times.
2）Tom and Jerry ____________(know) each other since they were at primary school.
3）Dad ____________(just take) the medicine.
4）She ____________(not hear) from him.
5）________ you ____________(see) Tony today?
03. 常用时间状语及其位置
>> 对比 for 和 since 的用法
【for + 一段时间】指持续了一段时间。
【since + 过去的时间点/ 过去的事件】指从过去的某个时间点，一直延续到现在。
注：ago“多久之前”，只能用于一般过去时。
>> already/ just/ still/ yet 的位置
观察例句，总结规律：
>> 现在完成时不与过去的具体时间连用
体会一下：
☑️ I have walked the dog.
我遛过狗子了。
可以表示：你不用再遛啦
❌ I have walked the dog yesterday.
昨天我已经遛过狗子？？？
1）表示过去某个时间发生的事情，只能用「一般过去时」：
I walked the dog yesterday.
我昨天遛了狗子。（仅仅表达昨天·我·遛狗这件事，和现在没有关系）
2）如果是未完成的时间，比如 today，this year，this month，this week 这类，可以用「现在完成时」。
I have walked the dog twice today.
今天我遛了狗子两次。（today 是还没有结束的时间，用 have done 表示“已完成”）
04. 难点
1）have been & have gone
have been“去过”
have gone“已经去了，还没有回来”
>> Tony has been to Japan twice.
托尼去过日本两次。（可能是去拜师学艺）
>> Tony has gone to Japan.
托尼已经去日本了。（下次再来剪头，托尼这会不在呢！）
>> Where have you been?
你去哪儿了？（你已经回来）
>> Where have you gone?
你去哪儿了？（你不在身边）
2）短暂性动作 → 持续性动作
在「状语从句」这节课中，虫子提到过这2个概念：“
短暂性动作，就是很短暂的、一瞬间就结束的动作，不能持续下去。比如起床 get up，眼睛一睁，起床的动作就完成了；再比如 die，断气的一瞬间就死透了。相反，可以延续的动作，比如你可以不带喘气地打3小时王者、跑5公里路、写8000字论文、睡到第二天下午…… 这些 play, run, write, sleep 等动作，就是持续性动作。
在现在完成时中，短暂性动词不能跟表示一段时间的状语连用（因为短）：
❌ Tony has arrived in Japan for a few days.
下飞机那刻就算到了，不跟 for…连用。
❌ The woman has left since her husband was sent to prison.
跑路也就是买个票走人的事情，短暂性动作，不跟since…连用。
❌ My rabbit has died for a week.
die 指断气的那一瞬间，不跟for…连用。
表示一段时间的状态，必须用持续性的动作。所以，上面的句子应该改为：
在现在完成时里，短暂性动词 → 延续性动词，有几组常用的，必须背的啊：
arrive → have been here
die → have been dead
leave → have been away
finish → have been over
borrow → have kept
buy → have had
获取完整版《短暂性动词 → 延续性动词表》
微·信·公·号：虫虫讲英语
后·台·回·复：现在完成时
05. 课后练习
提醒：现在完成时、一般过去时均有。建议拿出纸笔写下答案，做完后统一对答案。
Mary Morris ____________(apply) for her passport last month because she will soon be leaving on a trip that she ____________ (dream) about for many years. She ____________(work) as a receptionist at Ardmore's Travel Agency for ten years. All this time, she has been looking at pictures of exotic places on the wall and planning trips for others. For this reason she ____________(decide) to take an overseas trip herself.
After she ____________(plan) her trip, she ____________(make) her plane flights and ____________(reserve) hotel rooms. Mary doesn’t have to pay for her plane tickets because she ____________(work) at the travel agency for so long.
She ____________(want) take this trip for a long time, but each year her boss ____________(cancel) her vacation because someone else ____________(be) on vacation or someone ____________(quit).
Mary ____________(hear) about many exciting vacations over the years. Her boss, Ben, ____________(go) to Japan, Kenya, Alaska, France and Moscow last year. Meanwhile, Mary ____________(only see) these exciting places in photos! After looking at her boss' travel pictures, Mary ____________(decide) to take a trip of her own.
题目来源： grammar-quizzes
获取答案方式
微·信·公·号：虫虫讲英语
后·台·回·复：现在完成时
「虫虫讲英语」老少咸宜的英语学习号 —— 有时候，语法换一种方式讲，就听懂了。
06. 总结：
意义：9个字——已发生、持续性、影响性
结构：have/ has done
常用时间状语：
易混淆：have been“去过”；have gone“已经去了，还没回”
短暂性动作 → 持续性动作：
arrive → have been here
die → have been dead
leave → have been away
finish → have been over
borrow → have kept
buy → have had
呼，I have finished my homework! 终于可以开饭了，拜！
關鍵字: 完成 短暂性 短暂性动词→延续性动词表
