This one was suggested to me by my friend and fellow freelancer, Lyndsey Michaels, and is, indeed, an important one.
Of course, these two are linked, and formed from the verb to pass. And they are easy to confuse and HARD to explain! But that doesn’t mean that they shouldn’t be used correctly …
Passed is a verb and is the past tense of pass. It expresses the idea that something has gone by something else, or that anything that passes anything else has done so in the past tense. “She had passed the elephant house and was on her way to the penguins”; “Many years had passed, and he was an old man with only his memories of pandas to sustain him”.
If you can use the word “pass” in the present tense, the future tense, or use it in the form passing, etc., i.e. if you’re using it as a verb, a “doing” word, when you’re using one of the past tenses, or a conditional, you can use passed:
I will pass my driving test one day – when I have passed my driving test I will get a car – if I had passed my driving test, I would have been so happy – I have passed my driving test.
I am passing the jeering pub-goers with pride: after all, I’m running and they’re not – I passed the jeering pub-goers with pride – I will have passed the pub-goers in five minutes, and then I can relax.
Time will pass and all will be better – Time passed and all was better
Contrast this with past:
Past can be a noun meaning the time that has come before – “my divorce is in the past now, and I’m moving on!”. It can be an adjective – “Past prime ministers gathered for the Royal Wedding” meaning gone by in time and no longer existing. It is also a preposition meaning on the other side of “You can see him over there, past the crazy golf but in front of the candyfloss seller”. And it can be an adverb with a meaning of “so as to go by or so as to pass – “The ball went past the goalkeeper and the Mexican team scored”.
If something has passed something else, it has gone past it. It hasn’t past the other thing, and it hasn’t gone passed it.
So past doesn’t change when it’s used in the future, present past in a conditional sense, etc.: it works as a noun, an adjective, an adverb or a preposition and as an adjective, adverb or preposition will be found alongside a verb, rather than BEING a verb.
I went past the pub – I am going past the pub – I have gone past the pub – I will go past the pub – time will go past – the driving test was in the past – the driving test was in the past – the ball will go past the goalkeeper – the ball went past the goalkeeper – the ball was going past the goalkeeper.
You can find more troublesome pairs here and the index to them all so far is here.