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。
Robots differ from automatic machines ________ after completion of one specific task，they can be reprogrammed by a computer to do another one.
Iunderstoodfromherthatyouundertookotherimportantwork______.
_______, could you get me a Turkish conversation book?
Ithasbeenfoundthatastrong________helpovercometheeffectsofdistraction.