From Kaplan 800
Some analysts warn that, if the "numbers prove to be accurate", the entire SS system _________ in danger of failing.
(D) would continue to be
(E) will continue to be
I would like to know why D is incorrect. Per MGMAT, "If she ate pizza tomorrow, she would fall sick" is a correct sentence. Then, why isnt D? (If hypothetical event, X would Y).
Perhaps "prove to be accurate" is not in the hypothetical-past tense? Should it be "numbers were accurate" to make D correct? or perhaps "if someone proved the numbers to be accurate"?
Another reason why would seems appropriate here is that this is a prediction and doesn't seem 100% certain given the statistical nature.
Can someone please provide a clear rule of thumb on when to use will and when to use would, for a sentence:
If X (in the future), then Y would/will Z