danger作“危險”、“風險”講時，是不可數(shù)名詞；作“危險的人；危險因素；危害；威脅”講時是可數(shù)名詞；作“（壞事或不快之事發(fā)生的）可能性，危險”講時，既是可數(shù)也不可數(shù)，要從具體的語境當中看。

danger的用法

1.不可數(shù)名詞 danger of sth.危險；風險

（1）Danger! Keep Out!

危險！請勿入內(nèi)！

（2）Children's lives are in danger every time they cross this road.

孩子們每次過這條馬路都面臨著生命危險。

（3）Doctors said she is now out of danger (= not likely to die) .

醫(yī)生說她已脫離危險。

2.可數(shù)&不可數(shù)名詞danger of sth./danger that（壞事或不快之事發(fā)生的）可能性，危險

（1）There is no danger of a bush fire now.

目前不存在野外大火的危險。

（2）The building is in danger of collapsing.

這棟建筑有垮塌的危險。

（3）How many factory workers are in danger of losing their jobs?

有多少產(chǎn)業(yè)工人可能失業(yè)？

（4）There is a danger that the political disorder of the past will return.

昔日的政治動亂可能會重演。

3.可數(shù)名詞danger to sb./sth. 危險的人；危險因素；危害；威脅

（1）Smoking is a serious danger to health.

吸煙嚴重危害健康。

（2）Police said the man was a danger to the public.

警方說該名男子對公眾是個危險。

（3）the hidden dangers in your home

家里潛在的危險因素