The supply of silver in the mine had diminished , causing great concern among the people of the town.【同义替换划线词】

A. disappeared

B. erupted

C. expired

D. declined 

【答案解析】本题正确选项D。译文：矿井里的银供应减少了，引起了镇上居民的极大关注。解析：在四个备先项中，A项disappear“消失”；B项erupt“爆发，喷出”；C项expire“期满”；D项decline“下降；衰退”。题中划线词diminish“减少，降低”，和D项decline意思最接近，因此，依据题意在选项中最符合题意的选项是D。