Local opposition to fracking could leave vast tracts of the shale gas undeveloped .
地方上存在反对意见会导致大片页岩气矿脉得不到开采。
Herbivores require dietary fiber to move food through their long and bumpy digestive tracts , to prevent the bowels from becoming clogged with rotting food .
食草动物则需要可食纤维来帮助食物在它们那又长又凹凸不平的消化道中移动，以免肠道被发酵的食物堵塞。
Some nerve fiber tracts are also visible .
一些神经纤维束也是可见的。
People could write tracts to oppose the prevailing consensus , and with cheap printing those unorthodox ideas could gain enough influence to topple a king , or a pope .
That 's because acid rain produced by burning large amounts of brown coal has killed vast tracts of woodland , allowing wood-eating fungi to proliferate .
