Question

Two-thirds of the work _(be) done last week....​

Answer 1

Answer:

Was.

Explanation:

Two-Thirds of the work was done last week.

As supposedly, it is implicitly already given in the question that it wants us to change it in the past tense. " Last week."

Moreover, the verb is also given (be) and the past tense of be is "was"

I hope my answer was helpful.

Have a good day!