现在进行时怎样理解：现在进行时的定义及用法
现在进行时怎样理解：现在进行时的定义及用法He is now living in Shanghai.(指暂时住在上海）He lives in Shanghai.(指长久住在上海）what are you doing ?I'm writing a letter.要注意现在进行时的这一用法与一般现在时的区别。用一般现在时往往带有长久的含义，而用现在进行时则表示暂时的含义。
现在进行时是由助动词be的现在时形式（am is are）加-ing分词构成
1：表示说话时正在进行的动作
表示现在在做什么，通常要用现在进行时，能用于进行体的动词一般都是表示持续动作的动态动词。
eg:
what are you doing ?
I'm writing a letter.
要注意现在进行时的这一用法与一般现在时的区别。用一般现在时往往带有长久的含义，而用现在进行时则表示暂时的含义。
He lives in Shanghai.(指长久住在上海）
He is now living in Shanghai.(指暂时住在上海）
The Garden Bridge crosses the Suzhou Creek near the Shanghai Mansions.(不受时间限制）
Our bus is now crossing the Garden Bridge.(暂时经过）
2：表示现阶段一直在进行的动作
现在进行时也可表示现阶段一直在进行的动作，这种动作在说话时不一定正在进行。
eg:
Jane is studying law while her sister is doing physics.
I teach English at the Teachers' College but i'm now teaching in a middle school.
现在进行时的这一用法也表示一种暂时性。例如上述第二例用一般现在时表示一种长期的工作岗位，而用现在进行时则表示现阶段正在做的事。
He works in a chemical factory.(经常性工作）
He is working in a chemical factory these days.(临时性工作)
现在进行时常与always continually constantly for ever 等频度状语连用，对现阶段经常发生的动作表示某种感情色彩。
eg:
You are continually finding fault with me .
Joyce is constantly complaining that she is not properly paid.
She's always borrowing money and forgetting to pay me back.
The postman is always putting your letters into my letter-box.
现在进行时的这一用法与一般现在时的区别在于后者只是说明事实，而前者则带有感情色彩，并且多半表示说话人的不满情绪。
She complains about the house .(说明事实)
She is constantly complaining about the house .(表示说话人对“she”的行为的反感和厌烦）
3：表示按计划安排近期内即将发生的动作
现在进行时表示将来时间的用法。这种将来时态通常都是按照现在的计划安排近期内即将发生。
eg:
Mr Cameron is leaving China in a few weeks.
I'm going to Qingdao for the summer holiday.
We are meeting him after the performance.
When is Mr Manning taking his holiday?
现在进行时表示将来时间的用法还常见于某些时间状语分句和条件状语分句中。
eg:
I'll think about it while you're writing the report.
When you are talking with him take care not to mention this .
If you are standing at the corner i'll give you a lift(让你搭车） into town.
4:现在进行时的其他用法
a：表示刚刚过去的动作。
eg:
You don't believe it ? You know i'm telling the truth.
I don't know what you are talking about.
用现在进行时表示刚刚过去的动作只适用于口语中某些表示说话的词语，如tell talk say exaggerate等。
b:表示委婉口气。
eg：
I'm hoping you'll give us some advice.
I'm wondering if i may have a word with you .
现在进行时的这一用法只限于hope，wonder等少数几个动词。用i'm hoping 比用 i hope 口气要婉转一些，这种婉转口气是同现在进行时所表示的动作的暂时性、不确定性伴随而来的。
试试做下题目吧
1.My sister _ （live）at home for the moment.
2.You _(live) in North London don't you ?
3.Why that girl _(stand)on the table ?
4.Cheford Castle_(stand) on a hill just outside the town .
5.She _(see)her doctor twice a week.
