问道题目

我可以理解A是对的，但不理解为什么D不可以，谢谢

7. So poorly educated and trained are many young recruits to the United States work force that many business executives fear this country will lose its economic preeminence.

　　（A） So poorly educated and trained are many young recruits to the United States work force that

　　（B） As poorly educated and trained as many young recruits to the United States work force are

　　（C） Because of many young recruits to the United States work force who are so poorly educated and trained.

　　（D） That many young recruits to the United States work force are so poorly educated and trained is why

　　（E） Many young recruits to the United States work force who are so poorly educated and trained explains why