By law, a qualified physician can only prescribe medicine, protecting the pubic.

(A) By law, a qualified physician can only prescribe medicine, protecting the pubic.

(B) By law, only a qualified physician can prescribe medicine, protecting the public.

(C) By law, only a qualified physician can prescribe medicine which protect the pubic.

(D) In order to protect the public, by law a qualified physician only can prescribe medicine.

(E) In order to protect the public, by law only a qualified physician can prescribe medicine.

答案是E，怎么判断protect the public是目的？protecting the public如果用来修饰medicine，如B，为何不可？

感觉这里用in order to多是出于句子意思的考虑吧.doing在最后只能表示伴随和结果,不能表示目的.

本题的答案值得商榷（因为给的答案未必标准，毕竟不是ets给的）：

（1） 原文中，用的是protecting the pubic.在此只能是结果壮语。而答案E将结果状语改为目的状语，更改了原意。

（2）答案E有歧义。by law only可以理解为，只有按照法律规定。E可以有如下两种翻译

（a） 为了保护公众，法律规定只有有资格的人才能开药(by law ,only a qualified physician can prescribe medicine.)。

（b） 为了保护公众，仅仅按照法律，有资格的人能开药（by law only ,a qualified physician can prescribe medicine.似乎是说，还有不按法律也有有资格的开药的人）。

所以，我也觉得，B更好些。