Their greatest threat is becoming trapped in the irrigation canals. 对它们最大的威胁是会被困在灌溉渠里
The difference between day and night is becoming less and less perceptible. 白天与黑夜的区别愈发难以分辨
Food and water are becoming increasingly scarce. 食物和水愈发稀缺
The ice is becoming too weak to support a male polar bear. 冰面开始变薄 已经很难承受一只雄性北极熊的重量
It's now becoming clear that great whites migrate thousands of miles across the oceans 可以肯定的是 大白鲨长途跋涉数千英里横越大洋