今天我们要学的词是source。 Source, 意思是来源。 "Social Security is a reliable income source for seniors," 社会保障是美国老年人可靠的收入来源。 "Police have received thousands of tips, according to a source close to the investigation," 据了解案件调查进展的消息来源说，警方已经得到了好几千条线索。因为受沙门氏菌污染的影响，美国五亿多鸡蛋被召回。 "The U.S. Food and Drug administration is aggressively investigating the source...