onset n.

释义：the beginning of something, especially something bad

“onset”是个名词，意思是“开始”，常常可以用来完美替换常见的“beginning”。onset 表示“开始”时，后面常接有负向含义的名词，比如疾病、经济萧条、战争等。

例① 战争开始后，犯罪率激增。

Since the onset of the war, the crime rate has skyrocketed.

例② 有证据表明，会说一门外语有助于推迟老年性痴呆（dementia）。

Evidence shows that speaking a second language can help delay the onset of dementia.

例③最近的《经济学人》中也出现了 onset：

The study adds substantial weight to the evidence linking cannabis to the onset of psychosis.（“the onset of psychosis”指“精神疾病的开端”，这句话是说研究表明吸食大麻很有可能导致患上精神疾病）

翻译：经济危机爆发后，投资面貌发生了巨大变化。

Since the onset of the financial crisis, the investment has been changed dramatically.

（参考翻译：The investment landscape has been changed tremendously since the onset of the financial crisis.）