構(gòu)成 have /has +v 過去分詞
1基本用法：
① 現(xiàn)在完成時常用來表示一持續(xù)的動作或者狀態(tài)，也可以表示某一動作對現(xiàn)在產(chǎn)生的結(jié)果或影響，常常和just剛剛，already已經(jīng)，yet還，recently近來，ever曾經(jīng)，never決不，從不，still仍然，up to now 到目前為止，等一些詞語連用。譯成“已經(jīng)，一直”
e.g. the rain has already stopped. 雨已經(jīng)停了。
i have never broken my word. 我從來沒有違背過自己的諾言。
he still hasn’t finished his work. 他的工作還沒有干完。
② 表示動作發(fā)生在過去，但這一動作對現(xiàn)在有影響
e.g. i have got a letter from my aunt. 我收到姑媽一封信。
the lift has broken down . 電梯壞了。
they have taken the injured people to hospital. 他們已經(jīng)把傷員送到了醫(yī)院。
③常和for 及since 引導(dǎo)的狀語或者 how long 連用（v大多都是無限動詞，live ,study ,teach ,wait 等）
e.g. i haven’t seen you for ages. 我們好久沒有見面了
we’ve lived here for ten years. 我們在這里住了十年了。
they haven’t seen me since july. 七月以來，他們就沒有見過我。
how long have you known her? 你認識他多久了？
④常和since 引導(dǎo)的一些從今連用，譯成“自從-----”（主句用現(xiàn)在完成時，從句用一般過去時。）
e.g. i have learned a lot from him since i knew him. 自從我和他認識以來，我從他那里學(xué)到了好多東西。
you haven’t changed much since we last met. 自我上次見到你之后，你沒有太多的變化。
2 構(gòu)成：
①肯定形式 ：主語是第三人稱， has +v過去分詞 其他 ：have +v 過去分詞
②否定形式： 主語是第三人稱， has+not +v過去分詞 其他 ：have+not +v 過去分詞
③疑問形式： 把have/has 提前就可以了 have/has +主語＋v過去分詞
mary has made up her mind 下定決心not to go to the meeting 參加會議
mary hasn’t made up her mind not to go to the meeting
has mary made up her mind not to go to the meeting?
since自從――以來 ancient times遠古時代的 people have found various 多樣的ways 方法to preserve 保存meat肉。
since ancient times people haven’t found various ways to preserve meat.
have since ancient times people found various ways to preserve存meat?
3 have gone to 和have been to 的區(qū)別
have gone to 表示“去某地了”，而且現(xiàn)在還沒有回來
e.g. the children have gone to the zoo. 孩子們?nèi)游飯@了。（現(xiàn)在他們還在哪里，沒有回來）
have been to 表示“到過 /去過某地” 現(xiàn)在已經(jīng)回來了。
e.g. i’ve been to europe several times. 我去過歐洲好幾次了。（現(xiàn)在已經(jīng)回來。）
練習(xí)：09年理工類衛(wèi)生類閱讀理解
1 the spanish government西班牙政府 is so worried about 擔心the number of young adults still living居住 with their parents父母 that it has decided to help them leave the nest.窩，巢。
2 economists 經(jīng)濟學(xué)家blame 指責(zé)責(zé)備young people's family dependence on依靠 the precarious (不穩(wěn)定性)labour market 勞動力市場and increasing漸增的 housing prices.房子價格 housing prices have risen 上升17 percent百分之 a year since 2000 years.