Steppingstone
n. 踏脚石，达到目的的手段
🗣️ 情景例句
Play it safe.
做事要稳妥。
What are you looking for?
你正在找什么？
Meanwhile, a microphone, which was lowered into the mine two hours ago, has enabled the men to keep in touch with their closest relatives.
与此同时，两个小时以前放下井去的一只麦克风使井下的人可以与其亲属保持联系。