forerunners

1.Heavy clouds are the forerunners of a storm.

阴云密布是暴风雨的前兆。

2.overcast mornings are the sure forerunners of steady rain.

阴暗的早晨预示着肯定会有连绵阴雨。

3.The alchemists were the forerunners of the scientists of today.

炼金术士是今日科学的先驱。