比较结构问题，请教大家

eeheaven

. Although fruit can no longer grow once it is picked, it continues for some time to respire, taking in oxygen and giving off carbon dioxide, similar to the way human beings breathe(A) similar to the way human beings breathe
(B) similarly to human beings who are breathing
(C) just like the breathing of human beings
(D) as human beings when breathing
(E) just as human beings do when they breathe
我明白ABCD 为什么错，但是想问一下E中的DO指代的是什么， 一般这样的Verb 都是指代主句中的谓语动词， 本题中的谓语动词是continue ，但是感觉又说不通.

teddyabc

俺的意见：DO指的是take in oxygen and give off carbon dioxide. When fruit RESPIRES, it takes in oxygen and gives off carbon dioxide. When human beings BREATHE, they take in oxygen and give off carbon dioxide.