Definition: 1. An occurrence of death by accident, in war, or from disease.( 表示“（事故或暴力事件中的）死亡，死者”) 2. Helplessness in the face of fate.(命运面前的无力感) [Oxford Dictionary]

Example:

In contrast, road accident fatalities only occur because of an unexpected event.

与之相反，只有在出现突发事件时才会道路交通死亡情况。

I can barely think of any main road in our city which is not blighted by accidents and fatalities.

Definition: A person killed or injured in a war or accident.(死伤者): 1. A person or thing badly affected by an event or situation. (受到事件或情形严重影响的人员或事情) 2. The department of a hospital providing immediate treatment for emergency cases.(急诊室) 3. an accident or disaster.(事故或灾难)[Oxford Dictionary]

Example:

The egg was an early casualty of the cholesterol war.

鸡蛋是胆固醇之战的最早受害者。

The car industry has been one of the greatest casualties of the recession.

汽车工业是经济不景气最大的受害者之一。

He went to casualty to have a cut stitched.

他去了急诊室缝针。

Had the glass been in place, the casualty would not have occurred.

Definition: 1. The state of being subject to death. (必死性，必死的命运) 2. Death, especially on a large scale.(死亡，特别是大规模死亡) [Oxford Dictionary]

Example:

Many people knew someone who died, and it reminds people of their own mortality.

在很多人在知道某个人死了的时候，这一情况总让人想起他们自己必死的命运。

Infant and child mortality in the region is at least 50% higher than in neighbouring China.

这一区域的婴幼儿死亡率比近邻中国的婴幼儿死亡率至少高50%。

The mortality rate from cancer has fallen by 12 per cent in the last six years.