现在进行时和一般现在时的比较

暂时性动作和经常性动作

 计算机运转得很好。（暂时）The computer is working perfectly

 计算机运转很好。（一直如此）The computer works perfectly

持续性动作和短暂性动作

 车停了下来。（渐渐地）The bus is stopping

 车停了。（迅速）The bus stops

暂时性动作和永久性动作

 她现在住在农村。（暂时）She is living in the country

 她住在农村。（永久）She lives in the country

有感情色彩和没有感情色彩

 他在学校表现很好。（赞扬）He is doing well at school

 他在学校表现很好。（一般事实）He does well at school

过去进行时是由“ was +现在分词，  were +现在分词”构成的。

 昨天的这个时候我正在做作业。I was doing my homework at this time yesterday

 你昨天一直在等他吗？Were you expecting him yesterday?

 我进来的时候他们没在说话。They were not talking when I came in

 表示在过去某一时刻正在发生的动作或该动作与过去的另一动作同时发生

 昨天晚上七点我正在吃晚饭。I was having supper at seven yesterday evening

 她弹钢琴时我在看报。She was playing the piano while I was reading the newspaper

当句子意思很清楚时，我们也可以把两个动词都换成一般过去时。

 老师读课文时，我们都仔细地听着。We listened closely while the teacher read the text

 表示过去一段时间内正在进行的动作

 我们整个上午都在说你。We were talking about you the whole morning

 昨天下午从三点到五点他一直在看电视。He was watching TV at home from three to five yesterday afternoon

 表示按计划、安排过去将要发生的事

 他告诉我他很快就要走了。He told me that he was going soon

 她说她下个月动身去纽约。She said she was leaving for New York the next month

 表示故事发生的背景

 那支医疗小组往前线行进时天正下着雪。it was snowing as the medical team made its way to the front

 汤姆乘没人注意时溜进了房间。Tom slipped into the house when no one was looking

过去进行时可用来引出一个新的动作，这种用法颇有点儿像镜头转换。

 五分钟后，他已站在门口抽着烟。Five minutes later he was standing at the door smoking

 这婴儿在大声啼哭，突然，哭声停止了。The baby was crying hard and suddenly the crying stopped

 用来陈述原因或用作借口

 她昨天去看病了。她患了很严重的心脏病。She went to the doctor yesterday,  She was having a lot of trouble with her heart

 我作业没做完是因为我昨天一直帮妈妈在家干活。I haven't finished my homework because I was helping my mother at home all day yesterday

 与 总是，always,  经常， constantly, 等词连用，表示感情色彩

 这女孩老是改变主意。The girl was always changing her mind

 过去他总是向我要钱。in the past he was constantly asking me for money

一般过去时往往表示某一动作已经完成，而过去进行时却表示动作在持续或未完成。

 她昨晚给朋友写了封信。（信写完了）She wrote a letter to her friend last night

 她昨晚一直在给朋友写信。（信不一定写完）She was writing a letter to her friend last night

一般过去时表示只做一次动作，而过去进行时却表示动作反复地进行。

 她朝我挥了挥手。She waved to me

 她不断地朝我挥手。She was waving to me

 这男孩跳上跳下。The boy jumped up and down

 这男孩不停地跳上跳下。The boy was jumping up and down

将来进行时是由“ shall + be +现在分词，  will + be +现在分词”构成的。

 八点到十点之间不要给我打电话，我们那时正在上课。Don't phone me between eight and ten,  We'll be having classes then

 今晚你用自行车吗？Will you be using your bicycle this evening?

 明天八点她不在她的办公室开会。She won't be having a meeting in her office at eight tomorrow

 表示在将来某一时间正在进行的动作

 我不久就去度假了。I'll be taking my holiday soon

 他们会在车站接我们的。They will be meeting us at the station

 在口语中代替 will do,    shall do

 我希望你按时来。I hope you will be coming on time

 我明天将见到史密斯先生。I'll be seeing Mr  Smith tomorrow

 部长将就国际事务发表演讲。The minister will be giving a speech on international affairs

 表示原因、结果或猜测

 请你明天下午来吧。我明天上午有个会。（表原因）Please come tomorrow afternoon,  Tomorrow morning I'll be having a meeting

 抓住那个孩子，要不他会掉下去的。（表结果）Stop the child or he will be falling over

 你会出错的。（表推测）You will be making a mistake

 用在问句中，表示委婉礼貌

 你还要看点儿什么吗？Will you be reading anything else?

 我们什么时候再见面？When shall we be meeting again?

 表示稍后一点儿的安排

 这星期我们学第三单元，下周我们将学第四单元。The students are studying Unit three this week and next week we'll be studying Unit four

 我的任务在七月结束，之后我会回上海。My duties will end in July and I will be returning to Shanghai