If prices rise too high the government has to do something it. A. stopB. stoppedC. stopp

问题补充：

If prices rise too high, the government has to do something it.

A. stop

B. stopped

C. stopping

D. to stop

答案：

A. stop

B. stopped

C. stopping

(答案→)D. to stop

解析：动词不定式的用法。由句意“如果物价涨的太高，政府就不得不采取措施来阻止。”动词不定式在句中作目的状语，说明“采取措施”的目的是“来阻止物价上涨”。故选D。