OK, good points Navi (however note that medicine is uncountable - some medicine, so I think "a pill" would be better to make your point).navi said:Thanks Maxiogee and Timpeac,
I think the example I choose was -as usual- bad.
If I said:
a-All you have to do to stop this machine is push a button.
would you imagine that any button would do?
b-All you have to do to feel better is take a medicine.
wouldn't you immediately imagine that I am talking about a specific medicine?
Either 'the structure' itself is ambiguous and the context makes the meaning clear, or a and b are incorrect.