在现在完成时态中，be是have/has+been；在一般将来时态中，be是will+be。
如：Right now the new product is being developed in the laboratory.
An agreement has been put forward.
3．当用被动语态的时候，以下几点需要注意：
1）我们通常用by来引导动作的发出者，但当没必要提及动作的发出者或动作的发出者不重要，或很难说出动作的发出者是谁时，动作的发出者可以省略不提。
如：he believes that VR films will be accepted by viewers.
Both the headsets and the gloves are connected to the RealCine computer system.
动词give，lend，offer，send，tell和show后面可以接两个宾语，分别指人和物。当这些 动词用做被动语态的时候，我们通常把动词后面接的人做为句子的主语；有些时候，也会把物作为主语。
如：They are offered headsets and gloves in the cinema.
Headsets and gloves were offered to them in the cinema.
3）在主动语态中，一些动词后面往往接宾语和动词原形。在被动语态中，动词原形前面要接to。
如：I saw him go there. He was seen to go there.
4) 有时候，在被动语态中，get可以替换be。如：get changed, get dressed, get hurt 如：Please wait a while. I ll just go and get changed.
有些动词主动形式表被动含义。
如：This kind of computer sells well in China. Your article reads well.
状态动词不能用于被动语态。
如：I have many science books.
VR films belong to the latest wave of new technology.
被动语态的其它特殊形式：
it+动词的被动语态+that从句
如：It is said that the technology behind RealCine is virtual reality.
主语+动词的被动语态+to do
如：The technology behind RealCine is said to be virtual reality.
类似的动词还有：believe, report, suppose, know, prove 等。
二 情态动词和被动语态
1．在被动语态中用情态动词来表达能力，可能性，责任，允诺等。
如：Firefighter could be trained using RealCine.
2．情态动词被动语态的形式是：情态动词+be+动词的过去分词
如：The position of the viewer can be calculated at any time.
注意其它情态动词被动语态的用法：
主动语态 被动语态
Can touch can be touched
May feel may be felt
Might not impress might not be impressed
Could use could be used
Should use should be used
Ought to develop ought to be developed
