is our belief that improvements in health care will lead to a stronger more prosperous e

问题补充：

is our belief that improvements in health care will lead to a stronger, more prosperous economy.

A. As

B. That

C. This

D. It

答案：

A. As

B. That

C. This

(答案→)D. It

解析：句意：那是我们的信念医疗保健的进步将促进一个更强大,更繁荣的经济。这里是that引导的是主语从句，它在从句中不作成分，it是形式主语，代替真正的that引导的主语从句。故选D。