Passive

Hello, M88!
It sounds all so strange! Shouldn't you have "started" instead of " have started", because of "ago"? in 1) and 2)?
As for 3) , something is missing...
I'd say "this expression has been in/used/fashionable for 4 years now.

I think your original sentence is incorrect. It should be: "We started using this expression 4 years go.", because you have a definite time in the past. Alternatively, you can say "This expression came into use 4 years ago."

Then the passive structures will be:
1. This expression started to be used 4 years ago.
2. This expression started being used 4 years ago.
3. This ex

OOOOOOOOoooooooooooooooooOOOOooooooooooooppppppppsssss.....
Did I write it? OMG...forget this thread and delete it please...

1-This ex. was started being used 4 years ago.(simple past)
2This ex.has been started being used since 4 years ago.(present perfect)

Hi Mehrdad

I don't understand you sentences.
Why did you put the first sentence in passive? 'was started'? I think without the 'was' it'd be better.

I think your second sentence is quite weird, or I just don't understand it.
This exercise has been being used for 4 years (since 4 years ago)

Now it's clearer to me. What do you think?

Second sentence: "this exercise started being used 4 years ago"/or/"this exercise has been used for 4 years", that's what I would write...

Yes, I agree with you, Pieanne.

Thanks, Maverick. Where are you from?

From Israel. Why do you ask?

Just out of curiosity/interest!