However, a subgroup who rated echinacea's effectiveness highly on a form at the start of the study — and were given a placebo during the study — had the shortest duration colds.

然而，在研究开始时分发的表格中高度认同紫锥菊疗效、并在研究中得到安慰剂的那组病人感冒病程最短。

youdao

Points allocated to Healing Prayers increase the duration and effectiveness of spells that allow you to heal yourself and your Allies.

将点数分配到治疗祷言可以强化治疗法术的持续时间和效果。

youdao

Increases the duration and effectiveness of your Illusion spells, which deceive your enemies and hinder their movement and their ability to cast spells.

提高幻象法术(欺骗敌人并阻碍他们行动)的持续时间和效果。

youdao

People overestimated their chances of catching flu and the length of time for which the disease would be contagious, and underestimated the effectiveness and duration of the vaccine.

ECONOMIST: Flu vaccination

And the duration of this transition period must be agreed, and the effectiveness of security arrangements must be demonstrated.

WHITEHOUSE: Moment of Opportunity: American Diplomacy in the Middle East & North Africa | The White House