现在进行时讲解

         现在进行时的讲解与练习。

基本用法：

  （1）表示（说话瞬间）正在进行或发生的动作。
  （2）也可表示当前一段时间内的活动或现阶段正在进行的动作。

（二）谓语构成：be (am/ is/ are)＋v-ing （动词的现在分词）
  I’m watching TV now.
  They’re playing football.

（三）现在分词的构成。
（1）一般情况下在动词词尾加ing。
go→going             ask →asking               look→looking
（2）以不发音的e结尾的动词，去掉e加ing。
have →having      take→taking          make→making       write→writing
（3）以一个辅音字母结尾的重读闭音节，双写最后一个字母，再加-ing。
get→getting           sit→sitting             put→putting          run→running
swim→swimming         begin→beginning           shop→shopping

（四）现在进行时态的肯定式、否定式、疑问式及简略回答。
（1）肯定式：be＋v-ing            She is singing in the next room.
（2）否定式：be＋not＋v-ing           The students aren’t cleaning the room.
（3）一般问句：be动词提前。
肯定答语Yes，主语＋be，否定答语No，主语＋be not。
Are you playing the computer game?  Yes, I am. /No, I am not.
（4）特殊问句：对谓语动词进行提问的：What＋be ＋主语＋doing＋其他？
What is the old man doing under the tree?
对其他成份进行提问的，疑问词＋一般疑问句？
Where is the boy swimming?
Who is she waiting for?

三. 现在进行时与一般现在时的区别
（一）现在进行时表示动作的暂时性，而一般现在时表示动作的习惯性和经常性
I am watching TV now. （暂时性）
I watch TV every day. （经常性）

（二）现在进行时可表示短暂性动作，而一般现在时表示长久性动作。
Lucy is living in Beijing.（短时间居住）
Lucy lives in Beijing. （长久性居住）

（三）现在进行时表示的动作可带有感情色彩，而一般现在时所表述的动作通常是事实。
You’re always forgetting the most important things. （责备）
He is always helping others. （赞扬）
He often helps others. （事实）

（四）有些动词不能用进行时，know, understand, love, like, hate, wish, want, think, hope, have, believe, agree, hear, see, notice，等等。这些动词通常用一般现在时表示说话时发生的动作。
I have a lot of friends here.
She wants to buy a new bike.

【典型例题】
一、用括号内所给单词的适当形式填空。
1. Look! There __________(be) a lot of people over there. What __________they __________ (do) now?
2. —What __________ your mother __________ (do)? —She is a teacher.
3. It __________ (rain) heavily outside now. You must stay at home.
4. Don’t sing. The baby __________(sleep).
5. My brother __________ (not like) playing basketball, but he __________ (like) playing football.
6. —What _________ you usually _________ (do) on Sunday?
  —I usually _________ (stay) at home and _________ (do) my homework.
7. Listen! The girls _________ (sing) in the next room.
8. My sister _________ (want) to be a teacher.
9. It’s seven o’clock now. The Greens _________ (have) supper. 
10. He often _________ (swim) on Sundays. Look! He _________ (swim) at the pool.

二、单项选择
1. I want _________ homework now.
  A. doing               B. to do                C. to do my          D. do my
2. It’s time _________.
  A. go to school             B. play games        C. to go home       D. to do my homeworks
3. The boy is _________ to his teacher.
  A. saying                     B. speaking                  C. talking              D. telling
4. I’m _________ a book in the room.
  A. watching                 B. seeing                      C. reading             D. looking
5. Where _________ he _________ from?
  A. is, come                  B. do, come                 C. does, come              D. is, from
6. Do they have a new car? Yes, _________.
  A. they are            B. they have          C. they don’t         D. they do
7. He often _________ supper at 6:00 in the evening.
  A. have                 B. has                   C. is having           D. is eating
8. It’s 6 o’clock in the morning. He _________.
  A. get up              B. gets up             C. is geting up              D. is getting up
9. What are you doing? I’m _________ TV.
  A. watch              B. watches            C. to watch           D. watching
10. We _________ any Chinese classes on Friday.
  A. are having         B. aren’t having            C. don’t have       D. are have
11. Tom _________ an English class now.
  A. is having           B. has            C. having              D. have
12. Are you playing basketball? No, we _________.
  A. isn’t          B. aren’t               C. not            D. don’t