If more than one species is competing for a scarce resource, the competing species usually switch to different alternative resources.
如果一个以上的物种竞争稀缺的资源，竞争的物种通常会转向不同的替代资源。
2
Considered to be a less dangerous alternative to tobacco, "e-cigarettes" are taking over the West as more and more people switch over when trying to kick the habit.
随着越来越多的人开始戒烟，被认为危险程度更小的替代物——电子烟在西方国家流行起来了。
3
Other alternative input devices include single switch devices, devices that track head movements, and alternative keyboards for persons with mobility impairments.