Question

sporadic 【sporadic】adj.零星的Though polio has been practically wiped out, there have been sporadic cases of the disease.虽然小儿麻痹症已差不多被消灭，可是仍有一些零星的病例。

Accepted Answer

[spə'rædɪk] 
sporadicrecurring in scattered and irregular or unpredictable instances
Sporadic is an adjective that you can use to refer to something that happens or appears often, but not constantly or regularly. The mailman comes every day but the plumber visits are sporadic––he comes as needed.
A specialized use of sporadic is to describe a disease that appears only occasionally in random cases, and is therefore not an epidemic.  English borrowed the word sporadic from Greek sporadikós "scattered." A very near synonym is intermittent.
All forms of 'sporadic' will appear on average once every 3372 pages.sporadicsporadically

Front	sporadic
Pron	[spə'rædɪk]
Back	【sporadic】 adj.零星的 Though polio has been practically wiped out, there have been sporadic cases of the disease. 虽然小儿麻痹症已差不多被消灭，可是仍有一些零星的病例。
Vocab	sporadicrecurring in scattered and irregular or unpredictable instances Sporadic is an adjective that you can use to refer to something that happens or appears often, but not constantly or regularly. The mailman comes every day but the plumber visits are sporadic––he comes as needed. A specialized use of sporadic is to describe a disease that appears only occasionally in random cases, and is therefore not an epidemic. English borrowed the word sporadic from Greek sporadikós "scattered." A very near synonym is intermittent. All forms of 'sporadic' will appear on average once every 3372 pages. sporadic sporadically

Sporadic Appears Spə'Rædɪk Adj.零星的 Polio Practically Wiped Cases