presymptom

例句：

1. 1. The doctor noticed a presymptom of the flu before anyone else did.
   医生在其他人之前注意到了流感的先兆。
2. 2.The researcher discovered a presymptom of climate change in the data.
   研究员在数据中发现了一个气候变暖的前兆。
3. 3. The patient's symptoms were consistent with a presymptom of cancer.
   患者的病症与癌症的前兆相符。