forest应该是不可数的,我觉得应该看一下前后文,但这一句话要是continue加s可能是因为把这一片森林看成了一个整体了。
forest可作可数名词,又可作不可数名词
This is an oak forest. 这是个橡树林。
Most of the ancient forests in the world have been destroyed.
世界上大多数原始森林都被毁坏了。
a forest of skyscrapers 林立的摩天大楼
An airplane was swanning over a forest.一架飞机正在森林上空盘旋。
不可数。
但是前后的谓语单复数不一致是因为 这里强调的是整体还是整体里的每个都是。
像这样的还有family
A forest is an area with a high density of trees. There are many definitions of a forest, based on the various criteria.
forest 是可数的.
不可数