threshold of let-go current

例句：

1. 1. The threshold for entry is $500.
   进入的门槛是500美元。
2. 2. The researchers found a new threshold for detecting cancer cells.
   研究人员发现了检测癌细胞的新阈值。
3. 3. The temperature at the threshold of melting is critical.
   融化温度的临界点至关重要。