求教GMATprep中碰到的两道ＳＣ

suaster

There is a widespread belief that in the United States and western European that young people have a smaller commitment to work and a carrer than their parents and grandparents and that the some fo the change lies in the collapse of "work ethic"
(B)less of a commitment to work and a carrer than their parents and grandparents
(D)less of a commitment to work and a carrer than their parents and grandparents had
答案是（Ｄ）可是我觉得这里好象应该补的是did啊？


The success of the program to eradicate smallpox has stimulated expects to pursue what they had not previously considered possible better control,if not eradication,of the other infectons such as measles and yaws.
答案是　something they had not previously considered possible better control,if not　　　　　　　 eradication,of such infectons as measles and yaws.
哪位ＮＲ能分析一下这两个选项的比较啊？

suaster

明白了

谢谢啊！