have changed or have been changed

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23-Nov-2009, 08:16
san2612

have changed or have been changed

Please help me with this sentence. I don't know it should be 'have changed' or 'have been changed'

Theories about the causes of bird flu have changed/ have been changed in the light of recent research.
23-Nov-2009, 09:44
ha179

Re: have changed or have been changed

Not a teacher. 'in the light of sth' means 'after considering sth' so I choose 'have been changed'
23-Nov-2009, 09:47
sarat_106

Re: have changed or have been changed

Quote:

Originally Posted by san2612

Please help me with this sentence. I don't know it should be 'have changed' or 'have been changed'

Theories about the causes of bird flu have changed/ have been changed in the light of recent research.

The passive form 'have been changed' is correct. It will be clear from the active formation: The findings of recent research have changed the theories about the causes of bird flue.
23-Nov-2009, 15:46
RonBee

Re: have changed or have been changed

Quote:

Originally Posted by san2612

Theories about the causes of bird flu have changed~~/ have been changed~~ in the light of recent research.

What that means is that people changed their minds about the causes of bird flu after becoming aware of new information about the disease. If you use "have been changed" if means their minds were changed for them.

:-)
23-Nov-2009, 16:34
Excalibur

Re: have changed or have been changed

If you use "have been changed" if means their minds were changed for them.

Are you sure??

In both sentences, scientists must have changed their minds and amended the theories "in the light of (ongoing) research." But in both cases, it is the 'theories' that have changed -OR - have been changed by the scientists who have cogitated on the latest research.

'have been changed (by the scientists proposing the theories)' still refers to the theories. That these changes happened, implies that the scientists 'had another think'.
23-Nov-2009, 17:22
RonBee

Re: have changed or have been changed

You can use either one. Some will prefer one. Some will prefer the other. (I have stated my preference.)

:-)
23-Nov-2009, 18:22
Excalibur

Re: have changed or have been changed

The use, and preference, was not the issue.
In both cases, it was the theories that 'have changed/have been changed' - not that "their (the scientists') minds were changed for them." The latter is logically implicit in both sentences; but the the change of 'voice' from active to passive does not change the actual meaning.
23-Nov-2009, 19:37
bhaisahab

Re: have changed or have been changed

Excalibur is right, it is a case of change of voice from active to passive, the meaning doesn't change.