continual,continuous,successive,constant,persistent这些形容词均有“连续的,不断的”之意.continual：强调重复或持续发生,但连续之间允许有间断.continuous：语意最强,强调在时间和空间上没有间断.successive：强...把句子亮出来the rate of population increase of India has been —continuous—in recent years。he has been a —constant—source of strength and support