Manic depressives oscillate between depression and elation.是什么意思？

Manic depressives oscillate between depression and elation.

躁狂抑郁症患者抑郁与躁狂交替发作.

manic

adj. <医>躁狂的，患躁狂病的，疯狂的；n. 躁狂者；

例句
He seemed to have an almost manic energy.
他似乎有一股近乎疯狂的劲头。

depressives

n. 郁闷的( depressive的名词复数 )；

例句
Manic depressives oscillate between depression and elation.
躁狂抑郁症患者抑郁与躁狂交替发作.

oscillate

vt. 使振荡，使振动，使动摇；vi. 持续周期性地摆动，动摇，犹豫：犹豫不决，动摇，犹豫：犹豫不决；

例句
The design of high - frequence oscillate circuit can improve the reliability ofcharacter ofoperation and easy maintenance.
采用高频振荡原理设计振荡电路,提高了稳定性和可靠性.

between

prep. 在…之间，私下，暗中，在…中任择其一，来往于…之间；adv. 当中，中间；

例句
How big is the abyss between what you think you are and what you actually are?
你对自己的认识和真实的你之间差别到底有多大？

depression

n. 萎靡不振，沮丧，下陷处，坑，衰弱，减缓；

例句
It seems as if the blanket of depression is in some way necessary to help them blot out the even greater pain of real life...
似乎这种弥漫的抑郁情绪多少能帮助他们忘却一些现实生活中更大的痛苦。

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

elation

n. 兴高采烈，欢欣鼓舞，（病态的）欣快，欣快症；

例句
She showed her elation at having finally achieved her ambition.
最终实现了抱负,她显得十分高兴.