spontaneous/spontaneously

spontaneous /spɔnˈteinjəs/adj. 自发的，无意识的；自然的，天真率直的：make a spontaneous decision 自发做出一个决定；a spontaneous cheer from the crowd 人群中自发的欢呼［考句］ Nothing Helen says is ever spontaneous. She always thinks carefully before she speaks.海伦的讲话从来都不是突发奇想，在讲话前她总是进行过认真思考。

spontaneously n. 自发地：［考句］Although most dreams apparently happen spontaneously, dream activity may be provoked by external influences. 虽然大多数梦表面上是自发产生的，但外部影响也会使人做梦。