He mentions anesthesia is used to reduce the animals' pain and the experimented animals are kept in cleanconditions.
他提到麻醉可以用来减轻动物的疼痛，而且被用来试验的动物都是被放在干净的环境中的。
2
Poverty, malnutrition, overcrowding, lack of cleanconditions, pollution and limited health services are all causes of their poor health.
贫穷，营养不良，人口密度过大，缺乏清洁环境，污染和医疗设施有限均是导致健康不良的原因。
3
This paper presents the results of the experimental studies on the flashover characteristics of insulator strings under dry and cleanconditions applied with composite voltages.