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A fill in the blank from a school's worksheet. What bothers me is the word 'all.' Does it matter in deciding the verbs in this blank?
I ______ (work) on the project all night.
Without any context, it could be had been, have been, or simple past tense. Say:
I had been working on the project all night.
I have been working on the project all night.
I worked on the project all night.
Who knows which night? Last night, the night last week, or the night last year? So with almost all the blanks there!
Does the answer lie in the word 'all'?
What am I missing? What could be the answer?