[译] 仍然可以操作的风车磨坊只占很小的百分比。
[误] Only a small percentage of the windmills still works.

[正] Only a small percentage of the windmills still work.
[注] a...percentage of 并不影响后面的名词和动词，“windmills”是复数，因此后面的动词“work”也是复数形式，同样地如果percentage of 后面接的名词是单数，则动词也是单数，例如：“What percentage of her income is taxable?”