参考：无忧英语51talk梁颖老师的超实用语法20讲在线课程第1课
lesson 2时态 ：现在进行时
形式：am/is/are+doing
结构及变化：
肯定：am/is/are+doing
否定：am/is/are+not + doing
问：am/is/are+主语+doing？
答：yes, be/ no, be not.
特殊：Why/what + be + 主语 +疑问句？
现在分词变化规则：
1)一般情况+ing，going, playing,
2)不发音的e，去e+ing，taking, writing, leaving, breaking, making,
发音的e，seeing
3)ie结尾，变ie为y+ing, lie--lying, die--dying, tie--tying
4)重读闭音节“辅元辅”，双写末尾+ing, cutting, beginning, forgetting,
常见用法：
1)此时此刻正在进行
they are playing volleyball.
the teacher is speaking.
he is dancing.
实用句型：
I am writing to inform you something.
I am calling you to ---
表强调，带有感情色彩，如下：
don't rush me. I am working on it.
the neighbors are preparing for a party.
2)一段时间内重复进行的
目前一段时间一直在做，但此时此刻不一定在做
I am studying computer this term.
he is having pills three times a day. 最近每天吃三次药
I am learning grammar at 51 talk.
since I won the big prize, my telephone hasn't stop ringing. people are phoning to ask how I am going to spend the money.
3)现在进行时表将来
作用条件：可能性大的行为，即将发生的
come here! I'm coming. 马上来（还未动身）
瞬间动词在现在进行时一定表示将来。
the man is dying.
they are leaving.
they are getting married.
Tom is going to Italy.
I am writing a book.即将出书.
持续动词的进行只有有将来的时间状语或有将来的语境中才表示将来
I am travelling next month.
4)表示强烈的情感
don't rush me. I am working on it.
what are you talking about?
现在进行时与频率副词连用，表示说话者或褒义或贬义的感情色彩
常跟again, forever, always等连用，表示强烈抱怨或表扬
he is always helping others.
that car is useless. it is always braking.
oh no, not again. I am always making the same mistake.
typical. I am always forgetting my glasses.
they are always sending me a lot of trash messages.
he is always talking about you.
he is always doing that.
I am loving it.
be动词的进行时表示讽刺
he is being stupid.
he is being smart.
he is being polite.
现在进行时例句
Linda always does（一般现在时） her homework at night, but today she is watching （现在进行时）TV.
英文的两个简单句不能用逗号连接。可以用句号、分号、逻辑关系词连接。
I can't go out with you. it is raining out now.
I can't go out with you.，because it is raining out now.
phase 1
A: I saw Brian a few days ago.
B:Oh, did you? what is he doing these days?
A:he is at university.
B:what is he studying.
A:Psychology.
B:is he enjoying it?
A:yes, he says it is a very good course.
phase 2
A:hi, nicola. how is your new job going?
B:not bad. it wasn't so good at first, but it is getting better now.
A:what is about Daniel? is he OK?
B:yes, but he is not enjoying his work right now.
A:he's been in the same job for a long time and he is beginning to getting bored with it.