is our belief that improvements in health care will lead to a stronger and more prosperou

问题补充：

is our belief that improvements in health care will lead to a stronger and 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：考查it作为形式主语。本题的it是形式主语，真正的主语是后面的主语从句that improvements in health care will lead to a stronger and more prosperous economy.句意：我们认为医疗保健方面的改善会带来更强大更繁荣的经济。故D正确。