Re: Two-thirds of the apples are/is rotten. Use the same rule for fractions as for percents -
If it's a fraction of a plural, count noun, use are.
If it's a fraction of a singular noun, use is.
If it's a faction of a non-count noun, use is.
Half of the students were there.
Half the pizza is gone.
Half of the allotted time has been used. |