adv. 自发地，不由自主地；自然地
1.This one also happens spontaneously.
这个反应同样自发发生。
2."Variations in atmospheric circulation happen spontaneously," says Knight.
奈特说，“大气环流自然发生变异。”
3.For reasons that aren't yet well understood, cloned animals often abort spontaneously or are born with defects.
由于无法搞懂的原因，克隆动物通常会自行流产，或者具有天生缺陷。
4.The same or other users then spontaneously rated the pictures.
同时这些用户或其他用户给这些照片评级。
5.Which way will it go spontaneously?
哪条路径是自发的？
6.Falling asleep spontaneously during quiet times of the day.
白天安静的时候打瞌睡。
7.Many people spontaneously stood up and cheered.
许多人自发地站起来欢呼。
8.Her observations helped dismiss the popular belief that insects spontaneously emerged from mud.
她的观察有助于驳斥一种普遍观点，即昆虫会从泥土中自然出现。
9.Don't expect friendship to happen spontaneously.
不要指望友情自然而然的产生。