Question 22 is based on the passage you have just heard. 

听力原文

        (22) [Parents often hear that reading to their children is critical for supporting development, and the message is getting through to them.] In fact, in the United States, a little over half of children between the ages of three and five were read to every day in 2007, and 83% of children in that age group in the same country were read to three or more times per week in 2012. This is good news, because reading to young children helps their language and brain development. In fact, (23) [recent research has found that both the quality and quantity of shared book reading in infancy predicted later childhood vocabulary and reading skills.] In other words, the more time parents spend reading, the greater the developmental benefits in their four-year-old children. This is an important finding, but does it matter what books parents read? A new study has investigated this question. It followed infants across the second six months of life, and found that (24) [when parents showed babies books that had faces or objects with specific labels, they learned more.] This is in contrast to books that did not name images or books that had the same label under each image. Books that named different characters also promoted greater learning. So, what does this mean for parents? Not all books are created equal, (25) [so parents need to choose the books they share with their children with great care.] 

22. What does the passage say parents increasingly understand?（文章说父母们越来越明白什么？）

解析：C。录音开头提到，父母们经常会听说，给孩子读书对帮助他们发展至关重要，而父母们也正在逐渐接受这一点。C项与此相符，其中的Reading to their children原词复现，important是对录音中critical的同义替换，故为正确答案。

错项排除：录音中提到了孩子们的阅读频率和年龄，都是用于数据对比，与父母们越来越明白的道理无关，故排除A项和D项。B项在录音中无依据，故排除。