This is the 527th most frequent Chinese word.
下去
"To go down; to continue (an action or state)."
In this sentence, '下去' indicates the continuation of an action over time, in this case, talking.
请接着说下去。
Please continue speaking.
Here, '下去' conveys the notion of a change or progression in the state of something, specifically the decreasing temperature.
天气变得越来越冷了，未来可能还会冷下去。
The weather is getting colder and might keep getting colder in the future.
In this usage, '下去' suggests persistence and continuation in an effort or action, emphasizing determination.