单选题
1.Many people have made a______to a physical fitness program so as to maintain good health.
A.decision
B.commitment
C.contribution
D.difference
正确答案：B
答案解析：本句是带有不定式短语作目的状语的简单句。句意为“许多人都投入了身体锻炼计划，以保持良好的健康”。make a commitment“投入，保证”符合题意。