4. 现在完成时还往往可以同包括现在时间在内的时间状语连用，如：
now,up to these few days/weeks/months/years,this morning/week/month/year,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 been 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.

5.现在完成时往往同表示不确定的过去时间状语连用，如：
already（肯定），yet（否定，疑问），just,before,recently,still,lately,never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?

6.现在完成时的"完成用法"
现在完成时的"完成用法"指的是动作发生在过去某一时刻并已结束，但该动作对现在产生了影响，与现在情况具有因果关系。
例如：
He has turned off the light.他已把灯关了。（动作结束于过去，但说明的是现在的情况--灯现在不亮了。）
现在完成时"完成用法"的特点是动作不延续，因此：
该时态只能与表示不定的过去时间状语（如：already，yet，before，recently等）、频度时间状语（如：never，ever，once等）、包括现在时刻在内的时间状语（如：this morning / month /year...，today等）连用。
例如：Have you found your pen yet？你已找到你的钢笔了吗？
7.现在完成时的"未完成用法"
现在完成时的"未完成用法"指的是动作开始于过去某一时刻，一直延续到现在，或可能还要继续下去。
例如：
He has lived here since 1978.自从1978年以来，他一直住在这儿。
（动作起始于1978年，一直住到现在，可能还要继续住下去。）
I have been in the army for more than 5 years.我在部队已经呆了五年多了。
（动作开始于5年前，一直延续至今，有可能还要继续下去。）
此种用法的句中常需一个表示一段时间的状语（由since或for引导），或表示与现在时刻相连的时间状语（如：up to now，so far）等。
例如：
I have heard nothing from him up to now.到目前为止我没有他的任何消息。
注意：现在完成时的未完成用法只适用于延续性动词，不可用于终止性动词，即瞬间完成或延续时间很短的动词。
如：come，go，arrive，leave，join，become，die等。
8.一段时间+has passed+since从句
主语＋have / has been＋since短语
例如：He has been in the League for three years.
或It is three years since he joined the League. 他入团已三年了　　
9. 现在完成时常和短语 "up to now /till now","so far" （意思是从过去某一确定的时间一直延续到现在)连用。　　
Up to/till now he's read many story books. 至今他已读过好多故事书。
I've been to New York three times so far. 至今我已到纽约去过三次。
has gone (to),has been (to),has been (in) 的区别
has gone to：去了没回
has been to ：去过
has been in：呆了很久

考点名称：被动语态

• 语态：
  是动词的一种形式，它表示主语和谓语的关系。
  语态有两种：主动语态和被动语态。
  如果主语是动作的执行者，或者是说动作是由主语完成的，要用主动语态；
  如果主语是动作的承受者，或者是说动作不是由主语而是由其他人完成的，则用被动语态。

• 被动语态的构成:
  被动语态的基本结构：
  主语+be +过去分词(+by+动作的发出者）
  ① 一般现在时：am/is/are+过去分词
  如：Trees are planted every year.
  ② 现在进行时 am/is/are+ being +过去分词
  如：The road is being repaired. 
  ③ 现在完成时 have/has + been +过去分词
  如：The work has been finished.
  ④ 一般过去时 was/were + 过去分词
  如：The story was told by him.
  Many birds were killed last year.
  ⑤过去进行时 was/were+ being + 过去分词
  如： The new house was being painted when I got home.
  ⑥过去完成时 had +been+ 过去分词
  如： He told me that the work had been finished.
  ⑦一般将来时  will +be + 过去分词
  如：The problem will be discussed tomorrow.
  ⑧ 过去将来时 would/should +be +过去分词
  如： He said that the Christmas tree would be put up soon.
  ⑨情态动词的被动语态
  情态动词+ be +过去分词    
  如：The problem must be solved soon.
  Children should be taught to love animals.

• 被动语态使用注意:
  1. 不及物动词无被动语态。 如：happen, break down, come out......
  What will happen in 100 years.
  The dinosaurs disappeared about 65 million years ago.
  2. 有些动词用主动形式表示被动意义。 如： write, sell, ride.....
  This pen writes well.
  This new book sells well.
  3. 感官动词或使役动词使用省略to的动词不定式，主动语态中不带“to”，但变为被动语态时，须加上“to”。
  例：make somebody do something→somebody+ be +made to do something
  see somebody do something→somebody +be +seen to do something
  A girl saw my wallet drop when she passed by.→My wallet was seen to drop by a girl when she passed by.
  The boss made the little boy do heavy work.→The little boy was made to do heavy work by the boss.
  4. 如果是接双宾语的动词改为被动语态时，直接宾语（物）作主语，那么动词后要用介词，这个介词是由与其搭配的动词决定。
  He gave me a book.→A book was given to me by him.
  He showed me a ticket.→A ticket was shown to me by him.
  My father bought me a new bike. →A new bike was bought for me by my father.
  5. 一些动词短语用于被动语态时，动词短语应当看作一个整体，而不能丢掉其中的介词或副词。
  We can’t laugh at him. →He can’t be laughed at by us.
  He listens to the radio every day. →The radio is listened to by him every day.
  The nurse is taking care of the sick man. →The sick man is being taken care of by the nurse.
  构成be+done.

• 主动句变为被动句所遵循的4个步骤：
  ①把原主动句中的宾语变为被动句的主语
  ②把动词变为被动形式即be +过去分词，并注意其人称和数随主语的变化，而动词的时态则保持不变。
  ③原主动句的主语如需要则放在by后面以它的宾格形式出现（注代词的宾格），如不需要则可省略。
  ④其它的成分（定语、状语）不变。
  
  不用于被动语态的情形：
  ①不及物动词没有被动语态
  这类动词有take place, happen, come about, break out, appear, disappear, last,  arise等。
  例如：A fire broke out during the night.
  ②某些静态动词不用于被动语态
  这类动词有have, lack, fit, hold, suit, resemble等。 
  例如：My shoes do not fit me.
  ③宾语为相互代词和反身代词时不用于被动语态
  例如：We should help each other.
  
  关于主动形式表示被动意义:
  ①系动词（如look, sound, smell, feel, taste, prove等）要用主动表被动，因为系动词为不及物动词，它们没有被动语态形式。
  例如：The building looks very beautiful.
  ②当open, close, shut, lock, move, read, wash, clean, cook, cut, wear, carry 等用作不及物动词且表示主语的某种属性时，通常用主动形式表示被动意义。
  例如：The book sells well.
  ③有的动词本身含有被动意味，通常用主动形式来表示被动含义。
  例如：Her eyes filled with tears.
  ④不定式to blame, to let用作表语时，通常要用主动表被动。
  例如：Who is to blame?
  ⑤某些“be+形容词+to do”结构中的不定式通常要用主动形式表示被动意义。
  例如：The book is difficult to understand.
  ⑥不定式用于某些动词（如have, have got, get, want, need等）的宾语后作定语时，如果不定式的逻辑主语就是句子的主语，通常用主动形式表示被动意义。
  例如：Do you have time to help us?
  ⑦在too...to do sth.和...enough to do sth. 这两个结构中，若主语与其后不定式为to do sth.被动关系，则该不定式通常用主动形式表示被动意义（有时也可直接用 被动式）。
  例如：The writing is too faint to read.
  ⑧be worth后的动名词要用主动表被动。
  例如：This movie is worth seeing.
  ⑨在need, want, require等少数表示“需要”的动词后的动名词用主动形式表示被动意义。
  例如：The house needs cleaning.
  
  表示“据说”的三类被动句型:
  ①It is said that...句式
  例如：It is said that thirteen is an unlucky number.
  ②There is said that...句式 
  例如：There is said to be plenty of oil off our coast.