"Disease can be diagnosed long before irreversible damage has occurred."
Why in the above sentence first part is in simple present tense but second part is in present perfect tense?
Which is going to be happen before "diagnosis" or "damage"?
Please also give another example.
Once irreversible damage has occurred, diagnosis of the disease is much less beneficial.
Here is another example from the BNC: "The Prime Minister was nodding agreement long before Mark had finished."
Last edited by probus; 26-Apr-2013 at 06:36.