root out
phrasal verbroot something/somebody out
to find the person or thing that is causing a problem and remove or get rid of them 找到并去除(祸根);根除 We need to root out corruption at all levels. 我们需要根除各级腐败。 The principal promised to root out the troublemakers. 校长答应铲除捣乱分子。
to find somebody/something after searching for a long time 终于发现(或找到)