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It would be unwise to predicate that the disease is caused by a virus before further tests have been carried out.

It would be unwise to predicate that the disease is caused by a virus before further tests.

Hi all,

I have got two questions about this. First, what are the possible differences between the first and the second sentence? Second, is there a reason for using the present perfect tense in the underlined part?

Thank you.

Best wishes,

PBF
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Hi PBF

I'd say that the present perfect (have been carried out) simply indicates the completion of "more tests" more clearly.
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To indicate the temporal meaning of before, an action clause or a noun that can be interpreted as an action should follow.

I turned off the oven before I left the house.
Things like that used to happen before the war.
[before the war took place]
We were ready before sunset.
[before the sunset took place]
*We were ready before the pencil.
[pencil has no temporal interpretation. A pencil can't 'take place'.]

I think the noun tests is a borderline case. -- to my ear, anyway.

?All I know is that she was feeling fine before the tests.

I prefer testing. It's more verb-like. before further testing.
Or leave have been carried out as is.

CJ
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Comments  
Right. So, in other words, they basically mean the same thing. Right?

Thanks again.

Best wishes,

PBF
Yes. Emotion: smile
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 CalifJim's reply was promoted to an answer.