先兆的英文：
a straw in the wind
foreboding
presymptom

参考例句：

The aura is perhaps the most talked about of the phases.
先兆期是被谈论最多的阶段。

Moral corruption is the forerunner of national decline.
道德败坏是民族衰落的先兆。

Coming events cast their shadows before
即来之事必有先兆

It is said to be an omen of misfortune.
那被认为是一种不幸的先兆。

An evil omen;a portent.
先兆不详之兆;凶兆

These faculae frequently are the forerunners of sunspot formation
这些光斑常常是形成太阳黑子的先兆。

Some strokes occur without advance notice
有些中风发作前没有先兆。

Some respiratory symptoms can be the forerunners of asthma.
一些呼吸道症状可能是哮喘病的先兆。

By developing a sight for aura you will be able to check both physical and mental health.
通过发现先兆，你可以对身心健康进行彻查。

A condition of hypertension occurring in pregnancy,typically accompanied by edema and proteinuria.
先兆子痫怀孕期间出现的高血压状态，通常伴有水肿和蛋白尿病

straw是什么意思：
n. 禾秆；麦管，稻草编织品；鸡毛蒜皮；用以作掩护的人，浅黄色
adj. 禾秆的；浅黄色的，无价值的，稻草人般的；假的

The tick is straw.
这是个草垫子。

Glass should be packed in straw.
玻璃器皿应该包扎在稻草中。

A drowning man will clutch at a straw
病急乱投医

wind是什么意思：
n. 风；吞下的气
v. 曲折而行；缠绕；使喘大气

The wind is blustering.
风在呼啸狂吹。

Wind power: Use of the energy in winds to produce power.
风力:利用风的能量来产生动力。

wind energy potential
风能潜力

foreboding是什么意思：
n. 预感,先兆,预兆

She had a sinister foreboding that the plane would crash.
她有个不祥的预感,飞机要失事.

The sailor's wife had a foreboding that he would not return
那海员的妻子预感到他将一去不复返。

The sailor's wife had a foreboding that he would not return.
那海员的妻子预感到他将一去不复返。