1. The thinner and higher the heel, the greater the risk of foot and back problems.
    鞋跟越细、越高，引起足、背疾病的风险就越大。

2. Some bamboo is thinner than your little finger. Some is much thicker than your waist.
    某些种类的竹子比小手指还细. 某些则比腰还要粗得多.

3. Because the dust becomes thinner the further we travel towards the outer edges of our own solar system.
    因为我们越是接近太阳系的边缘，尘埃就越稀薄。