This is because they grow beneath the ground, where the sun's light does not reach them. The green colour of plants is produced by the action of the sun's light. Plants grown in the dark are white and unhealthy.
这是因为它生长在阳光无法照射到的地下。只有在阳光的照耀下, 植物才会呈现出漂亮的绿色。生长在阴暗处的植物通常都只有病态的白色。
Sunlight is also necessary for the proper growth of a plant. The food which the roots draw from the soil, and the food which the leaves draw from the air, are changed by the action of light, and are made into starch and other substances which build up the plant. We need not wonder, therefore, that plants spread out their leaves to get as much sunlight as they can.
植物的正常生长同样需要阳光。根从土壤中汲取食物、叶子从空气中吸收养分, 而它们正是通过阳光的作用才能够转化为构成植物本身的淀粉与其他物质。因此, 我们看到的植物都会尽量伸展叶子, 获得更多阳光。也就不足为奇了。
Look at the curious shape of the flower. Do you see how it hangs on the end of a long flower-stalk, and how it always tries to face the sun? At the back of the flower are five small greenish sepals; then come five brightly-coloured petals , blue or white in the violet, yellow or purple in the pansy. The petals are of different shapes, and the lowest of them has a long, hollow spur. Inside the petals are five little yellow dust-spikes, and in the centre of the flower is the green vessel with a hooked top, which contains the young seeds.
注意观察花朵的奇怪形状。你有没有注意到, 它究竟是如何悬挂在一根长长的中空花茎顶端, 总是面向阳光的呢? 花朵的背面长有五片很小的绿色萼片；然后就是五片颜色明亮的花瓣：紫罗兰是蓝色或白色, 三色堇是黄色或紫色。花瓣的形状各不相同, 其中位置最低的一个长有长长的中空突起。五个黄色的小雄蕊位于花瓣之中, 而整个花朵的中间则是一根顶部呈钩型的绿色管状结构, 幼嫩的种子就包裹在其中。
The flowers of the sweet violet are rather small and darkly coloured, and they are not easily seen by insects. That is why the plant has such a sweet smell. It needs a strong perfume to attract the insects.
香堇菜的花朵不是很大, 颜色较暗, 所以昆虫很难发现。正因为如此, 它们才会发散出如此甜香的味道, 因为香味成为了它们吸引昆虫的有效手段。