现在分词作定语 状语的用法
现在分词在句中起形容词和副词的作用.现在分词用定语时相当于一个定语从句；作状语表示时间、原因、条件等时相当于一个状语从句.然而,我们在使用现在分词时应注意两方面的问题.
一、作定语
现在分词短语作定语通常置于所修饰的名词或代词之后,现在分词短语作后置定语时,应注意下列三点：
1.现在分词表示的动作和谓语动词表示的动作是一先一后发生而不是同时发生时,不能用现在分词作定语,应使用定语从句表示.如：
（误） The teacher criticized the student having broken the window.
（正） The teacher criticized the student who had broken the window.
（误） Do you know anyone having lost a car
（正） Do you know anyone who have lost a car
2.being可用状语或补语,但不可作定语.如：
（误） Anybody being outside after ten o’clock will be criticized.
（正） Anybody who is outside after ten o’clock will be criticized.
3.表示经常性或已完成的非进行动作的时候,不用现在分词作定语.例如：
（误） The boy bringing us milk everyday is my brother.
（正） The boy who brings us milk everyday is my brother.
二、作状语
现在分词作状语,我们必须注意以下四点：
1.现在分词作状语与谓语动词的时间关系.
现在分词所表示的动作与谓语动词表示的动作同时发生时,现在分词用一般式.如：
The secretary worked late into the night,preparing a long speech for the president.
He sent me an E-mail,hoping to get further information.
现在分词所表示的动作先于谓语动词的动作时,现在分词要用完成式.如：
Having suffered from heart trouble for years,Professor White has to take some medicine with him whenever he goes.
Having finished his homework,the boy went out to play football.
2.现在分词作状语与主语的关系.现在分词作状语时,其逻辑主语与句子主语必须保持一致.如果不一致,分词应有自己的逻辑主语,构成独立主格结构.如：
Looking out of the window of our hotel room,we could see lots of mountains around.
They came into the classroom,talking and laughing.
Mr.Smith being absent,the meeting had to be put off.
It being a fine day,we all wanted to go outing.
3.现在分词作状语时,前面可用连词when,while,once 等.如：
When talking to you,I always feel happy.
Be careful while crossing the street.
4.现在分词作状语时与主语之间不能有并列连词or,and,but等,因为并列连词连接的是两个并列的成分,而分词短语只是全句的一个状语部分,但分词与主语之间可用逗号.如：
（误） Having been told many times,but he still couldn’t understand it.
（正） Having been told many times,he still couldn’t understand it.