courage is to life what broth is to soup .

勇气对于生活就相当于肉汤对于汤汁（有点怪……）
A is to B what C is to D 的句式,意思是A相对于B来说就等于C相对于D
例：1 A nest is to a bird what a house is to a man
2 Honey is to a bee what milk is to a cow
3 Smell is to the nose what taste is to the tongue