Ben Ku Wrote:This is a tricky issue. Most English speakers would probably be able to select the right form without understanding the grammar behind it.
Suppose Robert left my house an hour ago to go to the market. I could say:
If Robert took street A, it would take him 5 minutes to get to the store.
If Robert took street B, it would take him 10 minutes to get to the store.
(If PAST, then CONDITIONAL)
Here, we're discussing the options of possibilities for Robert to get to the store. these are not hypothetical situations, but possible scenarios.
However, when we're talking about hypothetical situations that never happened, we would use a subjective construction.
If Robert had taken street A instead of street B, then he would have gotten there five minutes earlier.
(If PAST PERFECT, then CONDITIONAL PERFECT)
Here, clearly, Robert did NOT take street A, so the entire scenario is hypothetical. You can find this construction on page 113 in the 4th Edition of the Sentence Correction Strategy Guide. (Case 5)
So in your sentence:
Stacey would have gone to the party if she had known about it.
(CONDITIONAL PERFECT, If PAST PERFECT)
is correct since this is a hypothetical situation that never happened.
i can't seem to find (even outside of the mgmat SC guide) the conditional for you used here:
If Robert took street A, it would take him 5 minutes to get to the store.
If Robert took street B, it would take him 10 minutes to get to the store.
if simple past, would + infinitive
is this a valid conditional construction? what about just using
if present, then present?