Free radicals are believed to be a first important step in heart disease, cancer and the ageing process.

自由基被认为是心脏病，癌症和老化过程中重要的第一步。

youdao

The controlling step of the ageing reaction for the directing agent of zeolite L is directional polymerization between aluminosilicate oligomers or between aluminosilicate and silicate oligomers.

沸石导向剂陈化反应的控制步骤是低聚态硅铝酸根离子之间或低聚态硅铝酸根离子与低聚态硅酸根离子之间的定向聚合反应。

youdao

Given that uncertainty, and the spectre of an ageing population, it seems a sensible first step to save any surpluses.

ECONOMIST: Alas, a bigger surplus doesn��t bring better policies

The reforms have been welcomed by the Association of British Insurers (ABI) as "another positive step forward in tackling the challenges of an ageing society".

BBC: Social care: Inheritance tax freeze expected