OG13 SC 125 关于helping verb问题

zingtrigger

125. Today, because of improvements in agricultural technology, the same amount of acreage produces double the apples that it has in 1910.

(A) double the apples that it has
(B) twice as many apples as it did
(C) as much as twice the apples it has
(D) two times as many apples as there were
(E) a doubling of the apples that it did



OG里说，“the same amount... ptoduces is paralleled by as it did ( produce understood).”
可是Manhattan上有一条关于helping verb的规则是：“the verb should usually match the helping verb in tense. If you need to change tenses, repeat the whole verb in the new tense.”
这里produces是现在时，后面应该是过去时，为什么不是必须写成produced，而是可以写成did呢？
感谢大神前来解答！

zingtrigger

自己顶一下~

zingtrigger

刚刚看到RON对OG13 SC 139的解释，里面提到一个例子

halley's comet caused / did cause a worldwide sensation. Since they're the same words, you can omit them.

这里的caused和did cause是一样的。所以125这道题是不是可以这样想，produced=did produce，而produce在前面已经出现，所以可以省略而只保留did呢？