突减

例句：

1. 1. The population has suddenly dropped by20%.
   人口突然减少了20%。
2. 2.The sales figures have plummeted,causing concern among investors.
   销售额急剧下降，引起了投资者的担忧。
3. 3. The temperature has droppedsignificantly overnight, making it feel like winter.
   温度在一夜之间急剧下降，感觉像是冬天。