这个城市的噪音污染已经超过了居民的忍受阈值。

The noise pollution in this city has exceeded the residents' ___thresholds of tolerance.

他进门时差点被门槛绊倒。

He almost tripped over the ___threshold when entering the room.

她站在成功的大门，既期待又有些忐忑。

She stood on the ___threshold of success, feeling both excited and a bit nervous.