Foreslope
前坡
🗣️ 情景例句
Please wait for me. I won't be long.
清等等我，就一会儿。
Take two pills and have a good rest.
吃两片药，好好休息一下。
a trough (the lowest point), a height (the vertical distance from the trough to the crest),
波谷（最低点）、浪高（从波谷到浪峰的垂直距离）