This is the most beautiful village _______ I visited these years.
D
分析句子成分后发现，visit为及物动词，所缺部分为宾语，所以应该选择关系代词。因为这里涉及到了最高级，所以只能选that。
Sincewehaveafocusedsubject，weshouldnottalk________.
Thefarmingmethodshavebeen________improvedwiththeinventionofthenewmachine.