Two days had passed since she had last eaten or slept.
Or should it be:
Two days have passed since she last ate or slept.
Or something else? And why? The combinatorial explosion of past simple, past perfect and present perfect is killing me.
Learn English – Is the usage of tenses correct in this sentence – “two days had passed since she had last eaten or slept”
past-tensepast-vs-past-perfecttense
Best Answer
Both examples are fine (the semantic difference is simply whether the "narrative time" is in the present or the past).
But it's unnecessary to repeat the Past Perfect with she had last eaten in the first version, since it's contextually obvious she last ate/slept before the passage of the two days. As a rule, native speakers don't tend to use Past Perfect repeatedly because it's stylistically cumbersome. Consider...
In short, example #1 is a valid construction, but I personally probably wouldn't use Past Perfect for the second clause. If you want to make things easier for yourself as a learner, I suggest you do likewise.