原文：专家提醒说，雾对人体健康的危害有很大的隐蔽性。译文：Experts caution that fog has great concealment of harmful effect on our health.
【正确答案】：改泽：Experts caution that the harmful effect of fog on our health is often concealed.
【题目解析】：“有很大的隐蔽性”应翻译为“… is concealed”，而concealment表示“隐藏手段”。
