比较中，谓语动词是have or 带有 will or can 的情况

这个问题很困扰我：
I have a bigger apple than you do 还是 I have a bigger apple than you have
I have finished homework earlier than you did 还是 I have finished homework earlier than you have
I will eat more apple than you will 还是 I will eat more apple than you do
I will finish homework earlier than you will 还是  I will finish homework earlier than you do
I can eat more apple than you can 还是 I can eat more apple than you do
到底哪个对？

There is a widespread belief in the United States and Western Europe that young people have a smaller commitment to work and a career than their parents and grandparents and that the source of the change lies in the collapse of the "work ethic."
(A) a smaller commitment to work and a career than their parents and grandparents
(B) less of a commitment to work and a career than their parents and grandparents
(C) a smaller commitment to work and a career than that of their parents and grandparents
(D) less of a commitment to work and a career than their parents and grandparents had
(E) a lessening of the commitment to work and a career that their parents and grandparents had
选D。最后用了had，而不是did.
我个人理解，欢迎补充：
前面没有一般过去时(或者表达一般过去时含义的成分)，所以这里不会引起过去完成时的歧义。
其次，have和be都表达了状态，可以回忆一下关于be动词的并列，所以这里用had也是没有问题的。

I have a bigger apple than you do 还是 I have a bigger apple than you have
用do。
但是有一道题目很巧妙，gtr可以参考下：


I have finished homework earlier than you did 还是 I have finished homework earlier than you have
用have

I will eat more apple than you will 还是 I will eat more apple than you do
要看逻辑含义，如果两个人都要开始吃饭，也就是还没吃饭，那么就用will.

I will finish homework earlier than you will 还是  I will finish homework earlier than you do
同上.

I can eat more apple than you can 还是 I can eat more apple than you do
用can.