提问

It is an oversimplified view of cattle raising  m say that all one has to do with cattle is leave them alone while they feed themselves, corral them, and to drive them to market when the time is ripe.

B, all one has to do with cattle is to leave them alone to feed themselves, to corral them, and

C. all one has to do with cattle is leave them alone while they feed themselves and then corral them and

答案是C， 可是BE动词后能直接跟动词原形吗？没见过啊， 但也只有C的形式是对称的，请解释一下~

谢谢