题目

It’s a common phenomenon that modern people now have difficulty sleeping. Drinking milk is thought to be helpful. A warm drink of milk before bed has long been the best choice for those wanting a good night’s sleep. But now a study has found it really does help people nod off—if it is milked from a cow at night. Researchers have discovered that “night milk” contains more melatonin(褪黑激素), which has been proven to help people feel sleepy and reduce anxiety. The study, by researchers from Seoul, South Korea, involved mice being fed with dried milk powder made from cows mi20÷2525=45=(   )20=128128：160=8080%