For example: a long and continual war; five years of continuous warfare. But continuous has a sense of being unbroken and non-stop.

　　Unlike continual, continuous can be used to refer to 空间和时间。For example you can say the development forms a continuous line along the coast.

　　Continual, 一般用来形容频繁发生但是有间隔的那种持续。For example, the bus service has been disrupted by continual breakdowns.

　　总之，continuous 比 continual 的使用更为普遍一些，比如在牛津字词库里 continuous 就比 continual 的出现频率高出五倍。