When he rested sometimes, plum plopped plumb in front of him.

有时他休息时，李子会垂直地扑通地坠落在他面前。

Austrian psychologist Fritz Heider began plumbing the depths of this question in the 1920s when he was developing what's now known as the Attribution Theory.

奥地利心理学家弗里茨·海德在20世纪20年代开始深入探索这个问题，当时他提出了现在广为人知的归因理论。

Using an underwater robot, researchers from the Sansha Ship Course Research Institute for Coral Protection plumbed the depths of Dragon Hole, in the Paracel Islands in the

三沙船航珊瑚保护研究所的研究人员使用水下机器人探测了西沙群岛龙洞的深度。

Researchers were able to plumb Europe's history in such great detail because they could take advantage of 150 years' worth of remains that have been stored in museums there.

研究人员能够如此详细地探究欧洲的历史，是因为他们可以利用欧洲博物馆中保存的 150 年的遗骸。