《When was it invented?》PPT课件16

《When was it invented?》PPT课件16

Here is a big box .Fisher(费希尔）invented it in 1901. It’s very hard-working. It can make your clothes clean and your  housework easy. With its help you can have more time to relax or to work.

What’s it used for?

It is used for washing things.

Who was it invented by?

It was invented by Fisher 

When was it invented?

It was invented in 1901. 

... ... ...

What invention are they talking about?

The zipper.

Who invented the zipper?

It was invented by Whitcomb Judson.

When was the zipper invented?

In 1893.

When was it used widely?

In 1917.

Where can you see zippers?

On dresses, trousers, shoes, bags,… almost everywhere.

... ... ...

discover, invent和find都是动词, 它们的词义相近, 但是有区别:

★discover意为“发现”, 指发现某种本来存在,但以前未被发现或未为人所知的事物或现象。

The lost bike was discovered at the bus stop. 

丢了的自行车在公共汽车站那儿找到了。 

Later I discovered that he was so kind.

后来我才发现他那么善良。

★invent 意为“发明”, 指发明以前不存在的东西。

Do you know who invented the computer? 你知道谁发明的电脑吗？

★find 意为“找到, 发现”, 指偶然发现或几乎没有困难地发现。

I found some old photos in that drawer.我在那个抽屉里发现了一些旧照片。 

... ... ...

主动句变为被动句所遵循的4个步骤：

1. 把原主动句中的宾语变为被动句的主语。

2. 把动词变为被动形式即be+过去分词，并注意其人称和数随主语的变化，而动词的时态则保持不变。

3. 原主动句的主语如需要则放在by后面以它的宾格形式出现（注代词的宾格），如不需要则可省略。

4. 其它的成分（定语、状语）不变。

被动语态的运用:

（1） 不知道谁是动作的执行者或没有必要知道谁是动作的执行者时。

The house is quite old. It was built in 1950. 

这座房子太旧了，它是1950年建的. When will the road be opened to traffic?

这条路什么时候通车?

（2） 需要强调动作的对象即宾语时。Calculator can't be used in the math exam. 

计算器不能用于数学考试。He was awarded first prize in that contest. 

他在比赛中获得了第一。

... ... ...

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