This time, they aimed for a lower blood alcohol level of about 0.03, and this allowed them to use a placebo control group — that's low enough that people might not have known whether they were drinking or not.

这一次，他们的目标是将血液中的酒精含量降低到 0.03 左右，这样他们就可以使用安慰剂对照组——这一酒精含量极低，人们可能不知道他们是否正在饮酒。