这段文字是毕业论文里的,怎么翻译成英文,最好是被动语态

被动语态中主语是动作的承受者而不是发出者 结构为主语+be的过去式+动词过去分词（不是过去式） 有时在句末+by sth/sb(动作的发出者)

Do the students water the flowers every day?

Do the flowers were watered by the students every day?

tom gave mike a pen yesterday

Mike was gaven A pen by mike yesterday

they will sing an english song at the party

An english song would be singd by they at the party.

或者

an english song at the party would be singd by they

英语中的被动语态使用得比汉语要多，要普遍，许多课本乃至实际应用中都常常涉及到这个问题。一般说来，当强调动作承受者，不必说出执行者或含糊不清的执行者时，多用被动式。须注意的是，许多地方与汉语不同。注意那些汉语中没有"被……"的意思，英语却用被动态。还要注意，英语的被动态往往由"by"引出，而有用介词"by"的短语往往又不是被动态，而是系表结构。还有些待殊现象，如…knownto man(人类......所知)，on foot步行(美国人有时用by foot)，in carraige(乘四轮马车)等等。还有假主动，真被动的十几个常用词的用法，以及so heavy to carry而不用so heavy to be carried等习惯用法。有关这类情况，做到心中有数对全面掌握被动态，准确无误地解答习题非常关键，被动态必须涉及的是动词的各种时态变化的问题。英语的时态本来很复杂，怎样记住各自的被动形式呢? 首先要明确"将来进行无被动，现在完成进行

同"。这两种时态无被动形式。

另外，不及物动词带有同源宾语的动词，反身代词的动词和系动词都无被动形式。即便如此，还有不定式，动名词，分词，以及它们的复合结构)的被动态，再加上情态动词，助动词以及它们的疑问式和否定式从中掺杂，真是令人头痛，眼花缭乱。下面口诀就以动词do为例，即do did过去式done过去分词，以口诀形式总结各种时态的被动态，一定对你有所启示。

被动语态的口诀

一般现、过用be done，be有人称、时、数变。

完成时态have done，被动将been加中间。

一般将来shall (will) do，被动变do为be done。

将来进行无被动，shall (will) be doing,

现在完成进行同，have (has) been doing。

现、过进行be doing, 被动be加being done。

情、助、有、是妥安排，一律随新主语变。

否定助后加not，疑问一助置主前。

主语恰是疑问词，直陈语序主在前。

一般情助加be done，双宾多将间宾变。

复合宾语宾变主，宾补、主补相应变。

第二句"be有人称、时、数变"即be有人称、时态和单、复数的变化。"情助"是指情态动词和助动词must，may，can，shall，will等一律随新主语(多是主动句中的宾语)来变化。"疑问一助置主前"是说有两个助动词的话，应把主语放在第一助动词之后或把第一助动词置于主语之前。下面详细举例说明之。

一般现、过用be done, be有人称、时、数变

例：1、主动：The children gave the foreign guests a warm welcome.

被动：The foreign guests were given a warm welcome by the children.

孩子们热烈地欢迎外宾。

2、主动：People regard him as brilliant.

被动：He is regarded as brilliant by people.

人们认为他很有才华。

以上两例都是一般时态用be done的例子，be有人称、时、数变，第三人称foreign friends是复数，时态一般过去时，所以"be done"就是were given，而People regard him as brilliant一句，被动后的"be done"就变成单数第三人称is regarded的形式了。

被动：

This speech was delivered by comrade Wang. (was delivered即一般过去时的被动态)

这篇讲演是王的发言。

There was a serious train accident near the border. Two people were killed and twelve were injured.

边境发生严重列车事故，二人死亡，十二人受伤。

A person who is truly honest is called a straight arrow. 直言不讳的人才是真正诚实的人。

A note was passed up to the speaker. 有人给讲演者递上来一张纸条。

John was elected president of the class instead of Harry. 乔治被选为班长而代替了亨利。

Volcanoes are described as active, dormant or extinct. 火山被描述为活的，沉睡着的，或者死的。

The soldier was killed, but the train was saved. 这位战士牺牲了，然而列车得救了。

He was thought to be clever but dishonest. 他被认为很聪明但不诚实。

The first zoological garden in the United States was established in 1874. 美国的第一个动物园是1874年建立的。

Families were often broken up; wives were taken away from their husbands and children from their parents. 家庭被拆散，妻儿被夺走。

The information is urgently needed. 急需这个资料。

Most environmental problems exist because adequate measures for preventing them were not taken in the past. 多数环境污染问题的存在，是因为过去没有采取适当的保护措施。

完成时态have done，被动将been加中间。

(过去完成时had done也包括在内)。

例：1、主动：We have studied English for 3 years off and on at the spare-time school.

被动：English has been studied for 3 years off and on at the spare-time school. (have随新主语变为has)

我们已经在夜校里断断续续地学了三年英语了。

2、主动: They had produced 100 tractors by the end of last year.

被动: 100 tractors had been produced by the end of last year.

到去年年底我们已生产出一百台拖拉机。

3、主动：They have set up a power station in their home town.

被动：A power station has been set up in their home town.

他们的家乡建立了一座发电站。

4、主动：They have warned us to be careful of rats.

被动：We have been warned to be careful of rats.

他们已提醒我们要注意老鼠。

5、主动：People have piled plastic bags full of rubbish in streets.

被动: Plastic bags full of rubbish have been piled in streets.

人们把装满垃圾的塑料袋子堆放在街上。

6、主动：We have used nuclear energy to produce electricity.

被动：Nuclear energy has been used to produce electricity.

核能已用来发电。

7、主动：No one has ever beaten him at tennis.

被动：He has never been beaten at tennis.

就网球来说还没有人是他的对手。

(No one涉及到全否定和部分否定问题，见否定一讲)

The person who owns the gun may try to deny that he has used it. But anyone seeing the smoke knows the gun has just been fired.

有枪的人会极力否认他开了枪。但是任何看到枪烟(枪冒的烟)的人都会知道刚才开了枪。

Today is Cilia"s wedding [font id=Mark style="COLOR: blue; BACKGROUND-COLOR: #ccffff"]day[/font], she has just been married to Danel. 今天是西丽亚的新婚日，她刚刚和丹尼尔结婚。

The subjects of these lectures have been announced by the lecture committee. 演讲委员会已宣布了这些讲演的题目。

过去完成时也是一样：

主动: Somebody had cleaned my shoes.

被动: My shoes had been cleaned by somebody.

有人早已把我的鞋子擦了。

When I returned I found that they had towed (toud) my car away, I asked why they had done this and they told me that id was because I had parked it under a "No Parking Sign".

被动：my car had been towed away. I asked why this had been done and told that ... it had been parked under a "No Parking Sign".

当我回来时，发现我的车被弄走了。我问他们为啥这么于。他们告诉我说因为我把车于停在"禁止停车"的禁区。

主动：They had build three ships by last December.

被动： By last December three ships had been built by them.

到去年年底他们已建造了三艘船。

Research had been centred on the improvement of natural building materials before synthetics were created. 合成材料造出之前，研究工作集中在改进天然建筑材料上。

He did not say if all those steel pipes had been examined. 他并没有说那些钢管都检验过没有。

After plastic had been created, engineers were given a much wide choice of materials. 塑料发明之后，工程师们在材料选择上有了更广阔的途径。

Application of capillary electrophoresis to separate the metal ions to explore. Using different cushioning system and the same buffer system, different concentration operation, to study various factors affecting the detection of metal ions. Experimental results show that the three-hydroxymethyl-methane concentration of 15 mmom / L, cetyltrimethylammonium bromide concentration