Researchers from the University of Michigan studied how 37 pairs of parents and toddlers interacted with e-books and paper books.

密歇根大学的研究人员研究了37对父母与幼儿用电子书和纸质书互动的方式。

A University of Michigan study had one group of participants take a 60-minute snooze, while a comparison group watched a nature documentary.

密歇根大学的一项研究让一组实验参与者小睡60分钟，而另外一组则观看了一部自然纪录片。

So why is it a University of Michigan study found that the percentage of minorities in leadership positions in US environmental organizations is less than 12 percent?

那么，为什么密歇根大学的一项研究发现，少数族裔在美国环保组织中担任领导职位的比例不到 12%？