現(xiàn)在完成時的用法
have(has)+過去分詞(done)
1.現(xiàn)在完成時用來表示現(xiàn)在之前已發(fā)生過或完成的動作或狀態(tài),但其結(jié)果卻和現(xiàn)在有聯(lián)系,也就是說,動作或狀態(tài)發(fā)生在過去但它的影響現(xiàn)在還存在.
I have lost my wallet.(含義是:現(xiàn)在我沒有錢花了.)
Jane has laid the table.(含義是:已可以吃飯了.)
Michael has been ill.(含義是:現(xiàn)在仍然很虛弱)
He has returned from abroad. (含義是:現(xiàn)在已在此地)
2. 現(xiàn)在完成時可以用來表示發(fā)生在過去某一時刻的,持續(xù)到現(xiàn)在的情況,常與for,since連用.
Mary has been ill for three days.
I have lived here since 1998.
3. 現(xiàn)在完成時往往同表示不確定的過去時間狀語連用,如already, yet, just, before, recently, lately等:
He has already obtained a scholarship.
I haven't seen much of him recently (lately).
We have seen that film before.
Have they found the missing child yet
4. 現(xiàn)在完成時常常與表示頻度的時間狀語連用,如often, sometimes, ever, never, twice, on several occasion等:
Have you ever been to Beijing
I have never heard Bunny say anything against her.
I have used this pen only three times. It is still good.
George has met that gentleman on several occasions.
5. 現(xiàn)在完成時還往往可以同包括現(xiàn)在時間在內(nèi)的時間狀語連用,如now, up to these few days/weeks/months/years, this morning/week/month/year, now, just, today, up to present, so far等:
Peter has written six papers so far.
Man has now learned to release energy from the nucleus of the atom.
There has bee too much rain in San Francisco this year.
The friendly relations and cooperation between our two countries have been enhanced in the past few years.
Up to the present everything has been successful.
6. 現(xiàn)在完成時表示現(xiàn)在之前業(yè)已完成的動作,雖然其效果或影響仍然存在但已不再繼續(xù),但是有一些現(xiàn)在完成時的句子,在后面加上for+一段時間,則現(xiàn)在完成時的動作就表示延續(xù)性.
Thomas has studied Russian. (現(xiàn)在不再學俄語)
Thomas has studied Russian for three years. (=Thomas began to study Russian three years ago, and is still studying it now.(同第2點用法第一個例句)
7. 現(xiàn)在完成時還可以用來表示過去的一個時間到現(xiàn)在這段時間內(nèi)重復發(fā)生的動作.
We have had four texts this semester.

現(xiàn)在完成時的“完成用法”和“未完成用法”
1.現(xiàn)在完成時的"完成用法"
現(xiàn)在完成時的"完成用法"指的是動作發(fā)生在過去某一時刻并已結(jié)束,但該動作對現(xiàn)在產(chǎn)生了影響,與現(xiàn)在情況具有因果關系.
例如：He has turned off the light.他已把燈關了.(動作結(jié)束于過去,但說明的是現(xiàn)在的情況--燈現(xiàn)在不亮了.)
現(xiàn)在完成時"完成用法"的特點是動作不延續(xù),因此,該時態(tài)只能與表示不定的過去時間狀語(如：already,yet,before,recently等)、頻度時間狀語(如：never,ever,once等)、包括現(xiàn)在時刻在內(nèi)的時間狀語(如：this morning ／ month ／year...,today等)連用.
例如： Have you found your pen yet?你已找到你的鋼筆了嗎?
2.現(xiàn)在完成時的"未完成用法"
現(xiàn)在完成時的"未完成用法"指的是動作開始于過去某一時刻,一直延續(xù)到現(xiàn)在,或可能還要繼續(xù)下去.
例如：He has lived here since 1978.自從1978年以來,他一直住在這兒.(動作起始于1978年,一直住到現(xiàn)在,可能還要繼續(xù)住下去.)
I have been in the army for more than 5 years.我在部隊已經(jīng)呆了五年多了.(動作開始于5年前,一直延續(xù)至今,有可能還要繼續(xù)下去.)
此種用法的句中常需一個表示一段時間的狀語(由since或for引導),或表示與現(xiàn)在時刻相連的時間狀語(如：up to now,so far)等.
例如：I have heard nothing from him up to now.到目前為止我沒有他的任何消息.
注意：(1)現(xiàn)在完成時的未完成用法只適用于延續(xù)性動詞,不可用于終止性動詞,即瞬間完成或延續(xù)時間很短的動詞.如：come,go,arrive,leave,join,become,die等.
(2)現(xiàn)在完成時常見兩種句型：
①主語＋have / has been＋for短語
②It is＋一段時間＋ since從句
例如：He has been in the League for three years.或It is three years since he joined the League. 他入團已三年了
一.have/has been doing sth.
1.現(xiàn)在完成進行時
當后面接有一段時間的詞時,或是加表示時間的詞時,可以用現(xiàn)在完成時.如果這件事現(xiàn)在還在持續(xù)或還在做,則可用
現(xiàn)在完成進行時.
如:I have been skating for 4 hours.
I have finished my homework.
2.現(xiàn)在完成時的被動語態(tài).
后接動詞的過去分詞.
如:The building has been built for 5 years.
二.一般現(xiàn)在時:用動詞原形
一般過去時:用動詞的過去式
一般將來時:will/shall+do
is/am/are going to do
過去將來時:could/would do
現(xiàn)在完成時:have/has done
過去完成時:had done
將來完成時:shall have done
過去將來完成時:would/could have done
現(xiàn)在進行時:is/am/are doing
過去進行時:was/were doing
將來進行時:will/shall be doing
過去將來進行時:would/could be doing
現(xiàn)在完成進行時:have/has been doing
過去完成進行時:had been doing
將來完成進行時:shall have been doing
過去將來完成進行時:would have been doing
此時態(tài)一般在中學學習